


N.Y.C sewers - Tales of the Hidden

by Chemistryofadream



Category: Teenage Mutant Ninja Turtles - All Media Types
Genre: Adventure & Romance, Alternate Universe, Alternate Universe - Dark, Angst and Romance, Danger, Dark Magic, Dementia, Demonic Possession, Evil Plans, Horror, Innocence, Mickey is cute as always, New York, Possession, Psychological Horror, Raph is unlucky, Romance, Sewers, Sound Effects, Splinter has got a lot on his shoulders, donnie is evil
Language: English
Status: Completed
Published: 2019-08-04
Updated: 2019-10-20
Packaged: 2020-07-31 04:43:40
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence, No Archive Warnings Apply
Chapters: 19
Words: 46,764
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20109334
Author URL: https://archiveofourown.org/users/Chemistryofadream/pseuds/Chemistryofadream
Summary: “Sometimes being a brother is even better than being a superhero." Marc BrownIs this always true?In the depths of the Big Apple sewers, lurk four well-known vigilantes. Well, at least three of them remain deeply devoted to justice. You probably don't want to know about the last one.Or... Do you?Follow the ninja turtles on a journey where evil may ambush them outside AND within their underground world...





	1. Sound hunting

**Author's Note:**

> Welcome to my AU TMNT fanfiction. I hope you will enjoy your reading and that it will stimulate your imagination, for I love to ask for input and opinions on how the story should go... Calling out to my dear TMNT fans! *Doctor Facilier's voice style*
> 
> All illustrations and cover are from me. I do fanart and original art on Instagram, Deviantart and Twitter under the same name (you can find me there if you want! Let's get crazier together *evil laugh*)
> 
> Disclaimer: TMNT are not mine, no money being made etc.  
Do not distribute or repost somewhere else (social media etc) without credits

Michelangelo was resting his back against the headboard of the bed, dreamily staring at the pipes above him.

_Ploc. Ploc. Ploc._

Small drops of water – or anything liquid enough to produce the sound – were falling and colliding with the edges of the hollow tubes. Creating an interesting rythm that had him quickly captivated.

He thought about his latest composition, « part of your seas ». He got hugely inspired by the Disney classic « the Little Mermaid » when playing it on his synthetiser. It was full of hope and memories of summer nights at April’s farm, dozzing under the stars on the roof of the barn. Only thing missing back then was an actual sea, but the nearest lake more then made up for it, allowing for wonderful swimming sessions in and under the cool water.

Such wonderfull mental pictures, playing before his eyes while he listening carefully to the natural rythm of the sewer water. It didn’t matter the color or smell of the so-called liquid ; only the sound counted.

He got up quickly and went looking for his recording device, meaning the external mic and the recorder connected to it, that Donatello had been nice enough to put together when they find it during a lucky scavenging trip – a small movie studio which had unfortunately caught fire. The mic had suffered a bit from the heat, but overall it still worked well enough for him to hunt and catch great sounds accross the sewers. Those made nice additions to his sound library for his tech-trance recordings.

The orange-masked turtle had landed himself a strange, yet exciting deal ; he would provide great music pieces under the nickname of « DJ Glasshell », be even paid for it by various nightclubs and organizers of festivals, and still be able to keep his identity a secret. Again, thanks to Donnie who provided for a fake and secured online payment account.

_Useful, nice Donatello._

Michelangelo repressed a shiver when he thought about the caracteristic smirk his brother had given him, when the youngest thanked him.

« You owe me I guess », he said with a weird tone and a even more weird glance.

Nothing warm, nothing even mischievous. It was rather malicious, like in the old sense of the word, straight from an evil thought.

Everybody knew it, even Master Splinter, but no one ever talked about. It was the greatest taboo of all, and they already had quite a few.

Rumaging through his things, the young terrapin finally found what he was looking for. Checking for the battery, he smiled at the nearly full indicator and powered the device up. Then, grabbing his headset, he went back to his bed and, standing up on it, tried to put the mic as close as possible from the pipes.

Luckily, everything seemed pretty quiet in the lair. Leonardo was probably meditating with their father, while Raphael was reading in his room – or punching his worn out bag, Mickey couldn’t tell for sure. He just knew that Raph wasn’t lifting weights in the dojo, since it was being used for the meditation session. Anyway, the muscular turtle hadn’t used it for quite a while, and again, everybody knew why.

The same reason he had to quit sleeping in his beloved hamac. Being deprived from those small pleasures had a serious impact on his mental well-being, and Leo had settled for a quest to find him one of those complex weight machines – the one allowing you to lift and work on your shoulders without having to lie down. However, those didn’t come cheap and everyone was kinda saving for it, without saying it out loud of course. They just convinced themselves that it would benefit the whole family.

Even Donatello seemed interested in the idea. Probably for selfish reasons, but still, any money could help.

At the thought of his purple-wearing brother, Michelangelo sighed loudly. He tried to focus on the task at hand, but no matter how close he tried to get to the tubes, he couldn’t get a satisfying recording of the dropping sound. It was too faint, at least for the recorder.

He needed to get closer, like, maybe, on the other side of the wall. Or even in the sewers. It had been a long time since he had gone sound-hunting. However, since… Recent events, Master Splinter had absolutely forbidden them to go anywhere alone, including the immediate vicinity of their underground and muddy world.

The young turtle reflected on his options. He considered asking Raph first, but remembering his current state of mind, he wasn’t sure it would be a good idea.

A fleeting thought about Donatello got immediately dismissed. Even if he was sure that somehow, his genius brother would find the trip quite amusing.

That was the frightening part, actually.

He decided that he would ask Leo. After all, HIS condition was the more… Under control. And it was their fearless leader, like Raph used to say. Nothing to be afraid of with someone as strong-minded as him, right ? No matter his current… Predicament.

Satisfied with his choice, Mickey jumped from the bed and landed gracefully on his tattered – and copiously stained – old carpet, and catching his bag on the way out, he slipped the recorder and mic into it. He was pleased to see he had already put the backup battery in the front pocket. Whistling happily, he went downstair and walked toward the dojo. He stopped two feet from the closed doors – and stuck his ear to the old wooden panel, trying to catch some clue on what was going on inside. He didn’t want to interrupt the meditating session yet, but they had been at it for nearly an hour now and it was getting a bit late. Soon, it would be night time – well, at last theirs – and he would have to go to sleep if he wanted to keep up with training tomorrow.

Muffled sounds could be heard from the other side of the door, meaning Leo and the old rat were most than likely beginning to clean up and pack the candles and meditation mats.

Michelangelo decided it was ok to interrupt now. He slowly opened the door, and then barged in with his trademark subtelty – Donnie might be creepy as hell, but at least he, Mickey, was the official elephant in the china shop.

Leo, busy with blowing the candles, raised his head and looked at his youngest brother.

_Gosh, would he ever be used to those eyes ?_

Gone was the pure, nearly silvered gaze of his eldest ; well, at least, you could still have a hint of the long-lost color behind those crimson, glowing pupils.

It wasn’t the only sign of what had happened to their leader, though.

He couldn’t help but wander from the red-lighted eyes to the blue horns that sit on the top of Leo’s head, like an obscene crown. Those were actually beautiful if you looked from up close, since they tended to sparkle like crystals, azure from a strange and damned world.

When Leo averted his gaze from Michelangelo, the youngest could tell he had stared to much. He fidgetted a bit, feeling a bit remorseful, then happily saluted his father when this one looked at him and smiled softly.

His eyes was unreadable, as always. With the same composed attitude, he turned back to the leader and just said :

« Remember what we discussed about, Leonardo. I will be in my room if any of you need me. »

And off he went. He stopped near Mickey though, like if something passed through his mind, his face harboring a curious expression. It’s like he knew that the youngest wanted to do something with Leonardo, not exactly something dangerous but still a risk to take, considering the situation. Yet, he kept silent, and left the dojo without looking back.

« Yo bro », Mickey said, gathering whatever enjoyment was left after such display of muted deep feelings – and sorrow. « Are you free now ? »

Leonardo sighed slightly. « Yes Mickey, I’m free. Do you want something ? »

« Well, I was wondering… » Suddendly, it didn’t seem like the best idea to ask Leo to come along with him in the dark, foggy sewers. It was the middle of October, and cold was quickly catching up with the season. They were beginning to feel it even in the lair, despite the heater already on. Donatello had also already checked the system to make sure it wouldn’t malfunction – probably willing to prevent any sickness from the turtles and their mammalian father.

Michelangelo was pretty sure it has nothing to do with him being thoughtfull for his family.

Leonardo was waiting, unconsciously reaching for his horns with his right hand. He did that a lot, lately. Once, Mickey had asked if they hurt. His older brother looked away and just said that « they had hurt, once, when they first came out ».

« Well ? »

« Sorry, I was daydreaming ! Silly me being me » Mickey said, trying to lighten the mood.

Fat chance it would work, but still.

Leo was now looking at the candles he still hold in his left hand.

« Would you like to escort me for a quick walk in the sewers ? I would like to do some sound hunting », the youngest continued, adding his brightest smile to his statement.

Leonardo considered the request for a moment, then took a defeated expression when he asked : « thanks for thinking about me, but shouldn’t you rather ask Raph… Or even Donnie… ? » He wasn’t so sure of himself with the second option, however.

They both fell silent for a few seconds. Then Mickey broke the awkwardness again :

« No will do, Leo. I want to go with you. »

He was really, really tempted to make some smart joke about the fact that the sewers wouldn’t be as gloomy as they usually were with the additionnal lighting provided by his brother’s eyes, but canned it. It really wasn’t a good time to make fun of Leo’s condition.

_Too soon._

It would probably be forever, too soon. Like with Raphael.

« Alright, I’ll go, just give me a minute », the leader said in a near whispering voice, grabbing some more candles and turning his shell to his brother.

Mickey was delighted. It wasn’t often that he managed to pull Leo out of his training and meditating sessions, and they didn’t talked much those days, except during their patrols topside. And even then, it wasn’t so lighthearted anymore. They only talked fighting techniques and strategy. Nothing very brotherly, nor fun.

Mickey offered to help with the candles, however, while Leo still kept his back turned to him, he just hurridly said that he could handle it alone. Relieved he didn’t have to do the chore (he had only asked out of politeness, really), Mickey turned around and left the dojo to wait for his eldest in the living room.

Little did he know why he had been dismissed. No did he see the slight shaking plaging the hands of his brother, while Leo was holding the candles.

On each of them, the flickering flame had been revived.

Simply because he looked at them.

A single, lonely tear sinked on his cheek and he blowed the candles once again, avoiding to look at them as he placed them on a shelf behind the weight lifting bench. The salty drop managed to fall on it, drawing a small, shiny circle on the dust that had accumulated on the vinyl.

It had been weeks, no, even months since Raphael had last used it.

Right after… The incident.

After that, the largest turtle could not allow himself to lie on his shell.

« Not ever again », Leo once heard him say.

He shivered at the memory, another tear running down his face. He wiped it off with an exasperated sigh.

He had to soldier up for his family. For Raphael. For Mickey.

Even for Donatello, he forced himself to add.

Once he was done, he turned off the lights that had been turned on by his father for their cleaning, and left the dojo. Mickey was waiting for him impatiently, fidgeting on the couch, his bag and equipment already ready.

« Alright Leo, let’s go then ! » He jumped up and went straight for the exit of the lair, looking back at his brother and smiling encouragingly.

It was a long time since they had actually done anything together, and Leo found himself looking a bit forward to it. A glimmer of hope, hope for things to get back to normal – at least as much of possible -, still lingered inside of him.

The leader could only hope, however, that everything would go fine. That the training provided by Splinter would be enough to keep control over… Everything.

Hope. He was amazed to see he was still able, somehow, to feel this way and believe.

The two brother silently went into the darkness of the sewers, Mickey taking his equipment out of the bag, along with a flashlight, clearly excited to share the trip with Leo.

Little did they know that another pair of eyes was following them through the various cameras installed in the sewers.

Sipping on his cold coffee in the shadows of the dimed lit laboratory, Donatello was silently staring at his screen, absolutely not bothered by the bitter taste of the cold beverage, and smirking, as the two shadowy figures progressed through the tunnels.

Things were becoming interesting indeed.


	2. Spying from the dark

**Summary for the Chapter:**

> Was it such a good idea to ask Leo in his current... State of mind?
> 
> At least Mickey got his precious bonding time with his big brother and leader, while two other turtles are not-so-friendly chating in the confines of the lair...

His eyes were shining in the dark – brown, almost reddish irises behind barely dilated pupils. Donatello was used to the shadows, maybe even more now than the fearless leader he was observing on his screen. 

It was an eye-catching sight, full of details that taught a lot to a careful observer. The slightly slumped shoulders of Leonardo, who carefully stayed behind his youngest brother. Michelangelo leading the way, probably beaming with joy, none the wiser. He was probably talking all along, enjoying his big bro’s presence, even if he couldn’t look at him while constantly blabbering. 

The genius could nearly hear the squeaky voice, and child-like exclamations of excitement everytime the youngest stopped to stick his mic against some wall or sewer pipe, while moving his head and arm in an agitated way. 

Oh, how Donatello found this never-ending speech of his maddening.

Not that he needed any help in that matter, his other brothers would have probably said. 

He was pretty sure, however, that Leonardo never really participated in the conversation. Probably keeping silent and maybe nodding from time to time, in the cover of the shadows around them. Mickey probably didn’t even see the head of his brother. Saved for those gorgeous, glowing crimson eyes he had now.

Donatello could feel the sting of jaleousy he always experimented when he thought about those eyes. Oh, what would he give to have them instead of Leo. But he wasn’t so sure about the price to pay. 

He needed to do more research before offering to trade, which he was absolutely sure, Leonardo would immediately refuse.

The evil possessing the leader was not welcomed as a good thing. Neither was the added strengh and the virtual immortality that came along with it. As far as Leonardo was concerned, living eternally while fighting over control of his own body and mind was definitely not a blessing. He couldn’t bear to see his brothers die, should it be from old age only, while being left alone in this cold and harsh world.

Maybe it was the only point Donatello agreed on. Their family was an essential part of his own existence, not out of consideration for their happiness and well-being, but because he was a damn mutant turtle, forced to live in the forgotten underground left by humankind. The sewers. How fitting for freaks like them. There was no emotion – there never was – in his train of thoughts, just cold ascertainment. However, contrary to his siblings, he had been endowed with a powerfull brain (quite lacking in the limbic aspect, but it was nothing to worry about), and could do a lot with it. He could prepare, analyse, work for the betterment of his condition – which would also benefit his family.

He needed them as the unavoidable unit at the core of his existence, the center of his life. A structured family life, preventing him from fighting too hard for his own survival. His brothers allowed him to purchase free time for experiments and research, and in exchange, he gave his own currency – taking care of the lair and repairing useful contraptions like the sound recording equipment of Mickey. It had its advantages too : the young DJ made some money out of it, and it benefited the whole clan. Donnie was in charge of handling the cash flow on the online payment account, but it was an easy task. He never stole any money from his brother. He didn’t have such petty needs.

However, he often ventured topside, pretending to make a run for the junkyard, when really he did visit his own favorite places : small laboratories, drugstores and even a research center, once.

Well, this one trip didn’t finish too well, did it ? 

As he watched his brothers, lost in his toughts, he suddendly mentally added Raphael to the small team exploring the sewers. He wasn’t there, but it was only by chance since they did most of their explorations as a team, nowadays. Driven by the circonstances. Or maybe, Mickey wanted some alone time to bond again with the leader.

Bonding time. How cute.

Donnie would have love for his bulky brother to join the little expedition, just to be able to look at his shell from afar. This incredible, beautiful result of major science experiments.

Well, once again, the turtle involved tended to disagree. 

The genius sighed, however keeping his mouth cornered in a small, cold smile. A quick command on the keyboard allowed him to turn the camera, ever so slightly, and focus on Leonardo, who was still hiding in the dark. He then saw what he wanted to see, a small consolation prize for the absence of Raphael.

Those two red, powerful glows. Only their quick disappearance, from time to time, showed that they were coming from someone’s eyes. 

Delighful.

Suddendly, a noise behind him alerted him and, before he could turn around and see who the intruder was, a voice – more like a growl, actually – rised into the darkness.

« The hell are you doing again, Don ? »

Talk about the devil…

« Watching over our two brothers of course, what else ? » the brainiac answered, smile widening up. He didn’t bother to turn around to greet the newcomer.

It probably wasn’t a courtesy visit anyway.

« Yeah ? Strange thing is, I don’t believe you… »

Raphael then stepped into the etheral light given by the screen, the only one in the laboratory. The genius didn’t exactly like to live in the shadows, but sometimes, he enjoyed to bask in the blue of his screen, attention focused on it, typing from memory. He didn’t need to see the details, only to concentrate on the task at hand.

The emerald-skin turtle took another step toward the screen and glanced at it. He frowned when he saw that his two brothers went away, alone.

« You see, I’m keeping tabs on them. Wouldn’t want something bad to happen now, would we ? » mused Donatello.

Raph turned around and stared at his brother, meeting his indecipherable – and sometimes, insufferable – gaze on him. 

« Oh, I’m sure you would just love that. Being able to observe when shit goes down because of Leo and his.... » Raph stopped then, a fleeting sadness veiling his eyes. 

Donatello took a mortified expression, one that didn’t suited him at all and probably was fake as one can be. Raph stood the gaze of his snake-like narrowed eyes, which were like two slits opening onto a dark world ; one sinking into madness.

Raph felt more than he understood, that his own vision was tunelling. Clenching his fists, he took a deep breath, recoiling from the screen and from his brother.

Everyone knew, no one talked about it. 

The greatest taboo of all.

The smartest turtle didn’t seem bothered at all by his strange behavior. He was merely ignoring him now, looking back at the screen. Despite the current situation, everything seemed quite… Peaceful, if Raphael could still use this word.

The calm before the storm ? He sure hoped not. He facepalmed a bit, wondering if he had come to hate his purple-banded brother – which wasn’t even wearing his mask right now, but was still proudly wearing what he called his « augments » - pieces of processed metal embedded on his own shell, to allow him to equip his pet project, an exosqueleton he called « HAL 5 », in tribute to the film 2001 : a space odyssey. Michelangelo had nicknamed it the « shell cheater », and it sure was some cheat considering it was weaponized as hell. Leonardo had made the genius swear he would never use this gamma gun – or whatever it was – on their enemis. Only on debris, foot mech or any other robot programmed to anihilate them. That robotic, merciless arm of HAL 5 was enough of a threat, whith its ability to strangle or slit one’s throat. And that one-eyed camera-thingie… Urgh.

They weren’t there to kill. But that creepy, intelligent robot sure was designed for this purpose. He was made of 4 parts : Don attached the central core to his own shell. He said that they shared some kind of neural connection, since he had implanted himself with some chip allowing him to communicate with it.

Raph wondered how Donnie could go with all those things attached to his shell, without feeling any pain.

Then again, feeling wasn’t the strong suit of his brother. 

The red-clad ninja looked at the screen again. Truth be said, Donatello wasn’t doing anything reprehensible at the moment ; just merely observing his brothers. Deep inside, Raphael wanted to believe that it was out of concern for them.

But he just knew better.

« Maybe I’ll join them. Looks like they’re going west from here. » Raph took a better look at the things Mickey was carrying around. The recording device.

Of course, they went sound hunting.

« The more the merrier », answered Donnie with an amused tone.

Raphael couldn’t pinpoint what was wrong this time with his bro, but again, everything was, all the time. He just had to pick one thing among the madness and the seemingly complete emotional detachment of his smartest brother.

« They will soon leave the covered area », the genius added, pointing at the screen. « Better hurry, don’t you think ? » he said with a sly smile.

His interlocutor suddendly felt like punching him in the face. 

« I knew you were waiting for something bad to happen, you… »

« Now, now. Let’s not use terms we’re going to regret, don’t we ? I already have a hint on what you’re about to say, so I’ll save you the effort. Furthermore… » Donnie added, absorbed in some afterthought, « I already told you I wish no harm to any of you ».

Raph looked at him once again, a dangerous sparkle in his eyes. He was feeling the rush of adrenaline inside of his body, torn between staying and giving a piece of his current state of mind to the evil genius of the family, or running away to protect his other brothers. 

He couldn’t believe anything this dude said. Not anymore.

Absorbed in their altercation, none of them noticed what was happening in the sewers behind them.

Mickey was still trying to catch some mix-worthy drop sound on his equipment, and grew kind of frustrated when he couldn’t manage to get a good rendering. Leonardo was remaining silent, as always, but the youngest still enjoyed his reassuring presence.

It was warm to feel this close to his big old brother again. He missed this connection, and wished for such events to happen more often. 

He would do everything he could to ensure just that. Even the cold, misty sewers felt more comfortable around Leo. In fact, it was like a warm campfire around them. Mickey didn’t feel the characteristic chill that came along with exploring the sewers around the lair.

Everything felt suddendly warm. Unusually warm.

Abnormally hot even…

Why was the nearest pipe shining with red suddendly, like if someone had freshly painted them with blood… ?

« Mickey ! Noooo ! »

Hearing the voice of his brother so suddendly, distorted in an high-pitched scream, made the orange-banded turtle make the fastest 180° turn he could manage.

Back in the lab, the two remaining brothers were coldly staring at each other. The space between them seemed cristallized in the air. 

« Of course. And I’m the Virgin Mary ». 

« You sure aren’t. But I must say, you’re my favorite fairy ! »

That was it. Raph was about to lunge at his brother when his eyes fell on the screen, and widened in horror. Surprised by his sudden stop and expression of pure terror, Don followed his eyes to watch the nightmare unfoding in the sewers.


	3. Rise of the Oni

**Summary for the Chapter:**

> When all hell breaks loose.

**Raphael point of view**

What he had seen on the computer was a crimson explosion. Like glowing blood, splattered on every walls and on the ceiling. The image on the screen had flickered for two seconds, before morphing into a static void.

Time seemed to stand still, before the dreadful realization reached his brain.

_There was no way he could reach them in time. _

Nonetheless, he had to try. He wasn’t even sure what was happening, but he could not possibly miss the meaning of this color – red, red everywhere, a cruel mockery of his favorite color. He had already seen it… The first time his brother’s eyes had changed.

His panicked, golden eyes made contact with his brother’s brown, reddish ones. His mind was blank, not able to properly register the emotionless features of Donatello’s face. Desperately, the sai-master rushed to the door of the lab, and running towards the exit of the lair, he disappeared into the darkness of the sewers. Heading west, he ran, breathless.

No time to think. No time to feel anything.

_Not even time to pray._

Unaware of the fact that he was being followed closely, Raphael ran to his remaining brothers, cursing fate and everything they have had to live through, lately.

**Michelangelo POV**

_Well, that’s it. I’m done for._

The young terrapin would have certainly thought that, if he wasn’t completely paralyzed and unable to form coherent thoughts.

A gigantic, nightmarish mouth, threatening to devour him whole, just stood a few feet from him. He was cornered against the wall, the pipe behind him hitting against his shell while he tried to back off on instinct. Then, an overpowering red light blinded him, preventing him from escaping ; he could only stare at those ominous fangs, and this dragon-like breath that threatened to burn his skin.

He was still clinging to his recording device and microphone, not even registering the fact that he was shaking them like crazy. All his attention was on this improbable mouth that was twice the size of his upper body, and could swallow him in one go – not before reducing him to turtle pulp, despite his shell.

Still, the demon seemed stuck, unable to come closer. Shaking himself out of his stupor, Mickey managed to catch sight of Leonardo behind the monstruous face of the demon, strongly clutching the lower part of the snake-like devil, pulling back with all his strengh and effectively preventing him from attacking. Trying to see behind the crimson, spectral abomination, the sea-green turtle could only see glimpses of the forest-green hands of his big brother, closed into tight fists around what looked like the tail of the Oni.

He wanted to scream his brother’s name, but thousands of voices suddendly rang into his ears, silencing him. He could only fall on his knees, finally letting go of the recorder who was still on. He desperately tried to protect his ears with his hands, but the gutwrenching clamor was coming from _inside_. Part of those voices echoing in his head ressembled Leonardo’s, and called for his name. But he couldn’t do anything ; the ruckus was unbearable, it reverbarated inside the very core of his mind. And above all, it hurt like hell.

Finally, unable to take more, he lost consciousness, falling face first on the ground and the little sewer stream that reflected the fight above him.

**Leonardo POV**

Nothing could describe the horror he felt right at this moment. The sinking feeling of maddening dread rushing through his veins, when he felt this powerful surge of heat – the astral flammes emerging from his own body.

This spontaneous, excruciating combustion that would leave him intact and consume his brother. He should have known the evil that dwelt within him would target his most vulnerable brother, to extinguish his bright spirit. To silence his insulting solar presence and joy.

He had dreamt of it, waking up startled, feverish and sweating. Images of tortures and screams echoing in his ears, long after the nightmare had left him. And here it was, everything he feared the most.

His sanity threatened to leave him. But he couldn’t afford to stay like that, in complete shock. Mickey’s life, their little ray of sunshine, was on the line.

Diving forward, he tried to catch the devil’s tail. He knew for a fact that the roaring Oni, who had emerged in a furnace of steam, still remained between two dimensions, where Leo was himself.

_Stuck in between, since that fateful day._

« _Don’t you dare try to stop me, mortal _» the voice hurt, like a rumbling fire in his entrails. He felt like burning alive, but still hold on. It was also deafening, but nothing would prevent him from protecting his brother.

« I will always stop you ! I will always be there to stand against you, unless you kill me ! »

Leonardo knew it was a dangerous game to play, but deep inside he knew the demonic entity needed him to be able to exist on the physical plane. This forced cohabitation inside one body didn’t suit the Oni at all, but he hadn’t much choice.

He would probably try to destroy all links tying his flesh puppet to human emotions, but wouldn’t succeed as long as Leo would be strong enough to contain him.

They struggled for a few more minutes, before the evil spirit began to lose the fight.

« _You’ll regret your impudence, fool _» he said in a menacing growl, before finally losing enough strengh to be forced to retreat inside of the leader. Whirlpooling inside his pupils, to the utter abhorrence of the poor katana-master – since it felt like having molten metal poured directly inside his brain, through his third eye.

An excruciating pain.

Leo then fell on his knees, like Mickey before him, trying to breath, vaguely catching the sight of the unconscious turtle lying on the floor a few feet from him, and the green light of the microphone still on.

Finally, as tears pooled in his eyes, the darkness swallowed him too.

**Donatello POV**

It wasn’t exactly what he had foreseen, but it was still valuable material to work on.

Firstly, the camera’s malfunction told him the Oni’s power was made, at least partly, of electricity ; not all type of energy rush was able to knock out such device (especially considering he had shielded it against natural elements, using some alloy of his own composition). He would be able to get a good measurement of this high energy intensity by taking a proper look at the camera – or what would be left of it. He also wandered about the thermal coefficient. With luck, he would manage to grab some altered copper in nearby electric wires…

Secondly, it happened quite fast, meaning the propagation probably worked like a strong blast. It came as a surprise to him ; he had thought it would emit some circular waves all around the summoner - well, if you could call Leo like that. It wasn’t exactly like he had intended for this event to happen.

Thirdly, it meant the eldest had poor control over the Oni in the offensive area, and that this demonic entity was quite powerful (not that they didn’t already know that for a fact). The leader managed to act fortress-like with his body on a daily basis, preventing the evil from « leaking » out too often ; but he wasn’t able – at least for now – to control potential outburst of demonic rage and aggression towards a close one.

Donnie wondered if Leo had harbored any ill-intention regarding his youngest brother, just before the incident.

He shook his head.

_Highly improbable._

He had to stay focused, since the red-clad turtle he was currently following constantly disappeared from his line of sight, taking turns like crazy. He was running so fast, it looked like he was flying.

The genius would have chuckled at the irony in other circumstances. But for now, in a certain way, he was also worried.

He couldn’t afford to lose two precious members of his family in a row.

He was mostly tagging along because he came to the conclusion that his medical skills would be needed fast. They hadn’t seen much before the camera died, but it didn’t look good.

Understatement of the year, probably.

**Normal POV**

When Raphael arrived, the walls were still glowing with this sick, red gleam –like if the place has fallen prey to a crimson dusk plague. The air felt heavy in his chest, and he came to a sudden stop when he saw his two brothers down – face first lying in the foul water.

He rushed to Mickey and pulled him on his shell, panting, sweating, eyes-wide open. He then grabbed Leo and did the same, proceeding to sit them like rag dolls against the pipes.

Those damn pipes Michey was probing for sound, just a few minutes ago.

He glared at the recording device which was still on, miraculously laying on a dry spot on the floor.

Recording the unbearable silence around them. The nothingness.

He put his face against their plastron, trying to catch any sign of life, even the faintest. It was really hard to hear anything behind the thick keratin, even a heart beat. But at least, he would feel it.

He breathed a sigh of relief when he finally managed to feel Mickey’s against his sensitive cheek. He rushed to Leo to do the same – but, as soon as he got close to his breast scutes, he heard something else. Something he didn’t want to hear.

Whispers. Coming from inside his brother’s body.

The bulky turtle shivered, but held his position. He just wanted a heart beat, damnit. To hell with this Oni and the frigging curse _it_ cast on their leader and the whole family.

_Hell. They were already there, weren’t they ?_

Forcing himself to ignore this deep, guttural voice that nearly sounded obscene to his ears, Raph finally managed to feel Leo’s rythm pounding against his dermal bones.

Then only did he feel another presence and, looking up, he saw Donatello, standing right in front of him, embracing the scene. He couldn’t tell how long his brother had been standing there, staring at them. And as always, he couldn’t tell what the purple-banded turtle was thinking.

He didn’t care. At least for now.

The genius’ gaze went from an unconscious Mickey to their leader, and back to Raphael.

« They are alive, just knocked out », Raph said while grabbing Mickey’s recorder and getting up.

Donatello thought that he could have told that by himself, from the way their breasts rose and fell softly, but refrained from voicing it out loud.

Raphael then spotted his youngest brother’s bag left against the wall, a few meters away. Head down, not looking at Don when he walked past him, the emerald-green turtle went to grab it and put the microphone inside,

« I’ll carry Leo. You take Mickey », he added. With great care, he lifted his brother's unconscious body and, securing him on his shell, started to walk back to the lair, still carrying Mickey’s bag, not waiting for an answer.

Donnie kept silent and simply did the same with his youngest brother, making a mental note to try and come back as soon as possible, in order to take some samples of this strange, red substance still glowing dimly in the darkness of the sewers.

Well, at least after making sure the others were ok.

Raphael was holding his brother tightly, making sure he wouldn’t slip and fall. The big turtle was still slightly shaking from his previous shock, and it was a real wonder his knees hadn’t given up while carrying Leo.

He prayed, from all his soul, that his big brother would be ok but would NOT wake up while being carried around on… THIS shell.

Donnie hadn’t said a word yet.

_It was better this way. _

They walked in silence, drops of filthy water falling around them in the nearby pipes, or feeding the little stream underneath their feet.

Like an endless rain of sorrow.

* * *

This wonderfull art has been made by the talented [RabiaNoor](https://www.deviantart.com/rabianoor) on Deviantart!


	4. Aftermath

**Summary for the Chapter:**

> Donatello only wishes to be able to study the devil’s ways, but Raphael and Master Splinter rely on him to take care of his brothers. 
> 
> Meanwhile, one blue-banded turtle slowly wakes up to face the harsh reality...

They finally arrived at the entrance of the lair. Master Splinter was already waiting for them there, deeply worried.

He was watching one of his soaps in his room when it happened. But truth be said, his eyes weren’t concentrating on the show.

Something felt horribly wrong. He had heard his two sons leave the place, but wasn’t sure he should tag along.

The fact that Donatello had deemed necessary to follow Raph had him the most concerned. He knew his smartest child, and the way he worked. Even if he never voiced his concerns, not even to his eldest.

Talking about Leonardo, he saw Raphael carrying him. Their eyes met, and Splinter could read everything he needed to know in those golden irises. Silently acknowledging, the old rat nodded and let them pass forward the laboratory, following their steps.

Donatello was absentmindedly carrying Mickey, his thoughts probably focused on what had happened. At least, they could count on his absolute self-control, since no internal struggle ever seemed to distract him.

_Did he even feel anything ? _

On his path to the laboratory, Raph turned on all the lights, as if he wanted to repel the shadows. Splinter saw Leonardo flinch a bit when he was put on the nursing bed, meaning he was slowly coming to his senses.

On the contrary, Michelangelo still seemed completely knocked out, while Donatello was placing him on the spare gurney with strange, unexpected care – and a frown on his face.

« What is it ? » asked Splinter, as he came to his side. The genius seemed to be concentrating on the features of his brother’s body.

« I don’t know yet, Master. But there is something… off with his blood stream. » He took the wrist of his youngest brother into his hands, trying to find the pulse, and relaxed a bit when he found nothing wrong with it. Mickey’s face looked peaceful, he wasn’t in any pain nor losing blood internally. It looked like he was deeply sleeping, nothing more.

Still, when Donnie was carrying him, he felt something unusal in the way his brother’s abdomen was moving. Probably nothing life-threatening, though, and it didn’t look like he had a broken rib or something. He would still need to take an ultrasound, just to stay on the safe side.

Not only was the olive-colored turtle a true mastermind for nearly every scientific field, he also had hightened senses and could feel the stream of blood, lymph and even qi in others’ bodies. He would have made a wonderfull traditional Chinese doctor. He was well-versed in herbalism too, and had studied acupuncture with an unsettling fervor. He always said it would prove more than useful in combat, whenever one of them experienced a sudden loss of blood or the need to be operated right there, on the field.

Charming, would have said the family, but at least, it was an useful tactical thought.

« What’s wrong with him ?! » the panicked voice of Raphael reached them from behind, while he left Leo’s side to come closer to them. Donatello answered with a shrug, but since he looked sincerely concerned for once – a rare, so rare occurrence –, the bulky turtle let it slip and focused his attention on Mickey. Meanwhile, Leo was stirring on his bed, wincing, eyes still closed in a pained expression. It looked like he was strugling against some feverish nightmare – but the old ninjutsu Master knew better.

« Tell me what happened, my sons. Do not omit anything », he said in a low tone.

Raphael averted his eyes, looking down. He couldn’t help but feel guilty. If only he had joined them immediately, instead of poking on Don.

Said turtle understood it was up to him to tell everything to his father, but he had to choose his words wisely. No need to get even more under the skin of his temperamental brother.

_Well, Leo lost control over the Oni_… No.

« The Oni managed to break free and tried to attack Mickey », he began._ While they were wandering alone in the sewers…_ No. Very poor choice of word again.

« Why did they go alone ? Only the two of them ? » the wise rat asked, without being told of course -, his voice quiet and measured, but he couldn’t fool Donatello. The genius knew his father was really close to holding them – especially him – responsible for this mess.

« I was monitoring them on my computer, Sensei », he added, withstanding the gaze of his father.

« Even if we went with them, I’m not sure we could have done anything… » Raphael interrupted, his voice reduced to a whisper by the end of the sentence.

Splinter considered what had been said for a moment, watching the red-clad turtle, then the bo-master. Raphael was the epitome of guiltiness, trying to hide tears of rage that threatened to invade his eyes by lowering his head. While Donnie simply supported his father’s gaze.

« I think you’re right, Raphael. We would only have add potential victims to this unfortunate event. From what I see, your brother was able to retrain the Oni and bring him back under the control of his mind… »

« He couldn’t prevent it from happening in the first place ! » The emerald-colored turtle suddendly bursted. He had enough of everything. How could they be so unlucky, damn it ?!

« Why is everyone only counting on HIM to contain such a powerful monster? I don’t even know how he manages to just LIVE with this… THING inside of him ! Day and night ! Fighting him even while he sleeps ! Just look at him right now » he yelled, turning around to point to his unconscious brother, who was still wiggling on his bed, sweating and panting. He looked like he was in terrible pain.

« We have to wake him up », simply said Donatello. Then, without adding a word, he took a small bottle on a shelf and, joining his eldest brother, he lifted him up in a sitting position and opened the vial right under his nostrils.

Leonardo only had to breath it once to wake up, red glowing orbes meeting the chocolate eyes of his brother who smiled – well, smirked – to him. The poor turtle turned his head to avoid the smell – and his brother’s gaze –, and started to cough violently.

« Leo ! » Raphael rushed to him, not without giving a death stare to the purple-banded turtle who had let go of the older turtle. « You couldn’t simply wake him up right ? » he vociferated.

« Calm down. It’s only ammonium carbonate salt, it’s not dangerous » Donatello shrugged. « Would you rather I slapped him ? »

« I don’t care what it is ! You heartless scientific freak and your fucking gimmicks… »

« Enough ! » the tone used by their father put an abrupt stop to their quarrel. Even Leo stared at Splinter with wide eyes, not getting a grasp of what was happening at the moment.

« Do not worry, my son, you’re safe in the lab with us », added Splinter with a mellow voice.

« Sensei… » the leader’s voice cracked under the emotion. Memories were flooding before his eyes. Mickey’s voice yelling, reverberating in the sewers. The pain endured by the possession.

_What he had done._

Suddendly panicking, he tried to get up. « Where is Mickey ?! I hurt him ! »

Raph jumped to force him back into a lying position, pressing on his shoulders. « Don’t move ! He is ok. Mickey is ok, you hear me Fearless ? »

Leo looked at him with mistrust.

« He can’t be ok ! The Oni… It attacked him ! »

« You probably managed to keep him at bay », said the genius in a neutral tone.

Three pairs of eyes fell on him.

« I’m saying this since Mickey doesn’t seem to be hurt. It is true, however, that he lost consciousness and I need to make sure everything is alright. But right now, I would say there isn’t anything life-threatening in his condition ».

Leo looked hagard, and awfully pale. Hearing the calm words of his brother, despite beeing devoid of any real emotion, helped a lot to calm his mind.

He slowly started to relax in the strong arms of Raphael, who was still holding him, clinging to him like a lifeline.

The red-banded turtle was scared, even if he would never admit it. Scared of the Oni, scared for his brother, scared for Mickey, their father and him.

And most of all, scared of Donatello and his cold, so cold mind.

He felt Leo press his forehead against his. He was still shaking slightly.

Raph had to soldier up for him. They both looked at the gurney, at the far corner of the lab, where Mickey’s motionless body rested limply.

« I will help Leo with his… condition. Donatello, I believe you wanted to proceed with some tests », the old rat said, placing a reassuring hand on the shoulder of his eldest son.

Nodding silently, the bo-master went away, looking for something. Raph remembered they had talked about an x-ray or something, probably to check for internal injuries. Sighting, the red-clad turtle finally let go of his brother. He got up in an awkward manner, trying to avoid turning his back to Leonardo who didn’t notice – contrary to the other turtle observing him from afar, while rumaging through his devices.

_He was still trying to hide his shell._

Donatello would probably never understand why his brother felt this way. The current state of his caparace was a blessing. An opportunity given by science. But Raph would probably never agree with him.

« What can I do…? » said turtle asked their father, a hand still lingering on Leo’s bed. He wanted to help so badly, to be able to relieve his brother of his burden… Even for a little bit.

If only his fearless brother hadn’t sought to be stronger… If only he, Raphael, hadn’t fallen into this tank back then…

« Thank you my son, but this is something your brother can only do alone. I will assist as much as I can, but this must be dealt with on the astral plane ».

Meditation. Of course. It definitely wasn’t Raphael’s strong suit. Cursing internally, he went back to Mickey’s side.

The young DJ wasn’t showing any side of waking up anytime soon.

« If you want to help, you can bring Mickey over here », he heard from behind. Don was wawing at him, pointing at their home-made echograph. Well, at least a handiwork of what could have been salvaged from various trips to depots for medical equipment, all accross the city. It took them ages to get enough parts for the device to work properly. But boy, were they glad when they could use it.

Internal injuries were no jokes, especially considering their day-to-day reality.

Raph pushed the gurney, which wheels came in handy in such cases, towards his genius brother.

He then leaned back against a naked wall – between shelves and shelves crammed with beakers, test tubes, charts and what-not. He tried to avoid, as much as possible, to bump into one of them with his damn shell while Don was working on their unconscious brother.

He still wasn’t used to the _extra parts_ and the – ever so slightly – _extra weight_, pulling on his back.

« Mmmm, there is nothing… Maybe I was mistaken... ? » Donatello was mumbling, focusing on the small screen which showed Mickey’s internal organs in the abdominal area. Looking at the pictures, Raph felt a bit sick. He really wasn’t good with medical stuff, even if he managed to do small patching for his brothers’ flesh injuries. Courtesy of the brainiac, who taught him as much as Raph would accept to learn. The sai-master knew that they could not rely on the family’s doctor everytimes things went down, let alone their old father. He had to be involved and prove himself useful too.

He even learned to do repairs, including sensitive equipments. He was quite skilled with his hands when it came to mechanics, and prouded himself on this fact.

However, it had been some time already that he hadn’t touched the Shell cycle.

Donnie’s voice suddendly interrupted his train of thoughts.

« There ! There is something… »

Raph approached them carefully and watched the screen, even if he had no idea what he was looking at.

« What ? » he asked the genius in an annoyed tone, to disguise his returning fear. The genius was staring, wide eyes, at some dark mass that the emerald-skined turtle could of course not identify.

« Missing… »

« What… ? » Raphael wasn’t sure he had heard his brother well.

« Missing. A part of his liver is… Missing ».

Raphael stared at the genius with disbelief.

_What did it even mean ?_

« What ?! How is that even possible ? Do you mean, he is badly hurt ? How come he is not bleeding ?! »

« No, it’s like… This part never was there ! Like it got… Shrinked. »

Raphael’s mouth fell off, his eyes jumping from the screen to his brother like crazy, and then to Mickey, who was still sleeping.

« Does it mean he is in danger ? Is he in pain ? »

« I don’t think so… I believe he can’t feel it yet. But it’s not good. »

« You bet it’s not good ! He is missing an organ ! What can we do ? There must be something we can do ! »

« A part of an organ », Donnie corrected. « And… I have no idea. »

With this, they both fell silent.

Donatello, from being confronted to his limits as a scientist, something he couldn’t stand. Raphael, from the shock.

Nervously, he looked back into the lab, in the direction of Leo to check if they had been heard. Fortunately, their father had already taken him away for their much-needed meditation session.

It was just buying them some time, and the red-clack turtle knew it. Sooner or later, they would have to tell Leo.

_And put him right after under suicide watch, probably…_

« Can’t you figure out something ? You’re the resident genius here, brainiac ! » he hissed at his other brother, clenching his fists.

« Even I have my limits », said-genius admitted, with a tone that had Raphael – and his temper – paralysed for a second.

Don sounded… Defeated.

« Wait, can he even live normally like that ? With an organ missing ? » Raphael added, gesturing at their brother on the cot.

« Part of an organ », the scientist corrected again, remaining calm. « And, I believe so… His readings look normal. I’ll check his pulse again. However, the liver is absolutely necessary for the proper functioning of our bodies. Us being mutants probably doesn’t change this fact… »

Blood cells. Hormones. Biochemicals. Donatello wasn’t about to list all the vital functions performed by the liver to Raphael, only to see him freak out even more. But he still carefully listed them in the back of his mind. Michelangelo may need a hormonal support afterwards. He wasn’t sure. He needed to check his blood results and monitor them closely.

« I'm going to take a blood sample from him ». He stepped away from the screen and went to search for a seringue, when he saw the state Raphael was in.

Close to completely losing it.

_Again_.

Bloody hell. What now? Leonardo and Splinter had a lot on their shoulders already. They couldn’t take care of a rampaging Raphael, destroying everything in outbursts of rage. And he, Donatello, didn’t need the distraction.

Sighing internally, he raised his hand to touch Raphael’s arm in a tentative, comforting gesture. He had no idea what he could do to give him solace or, at least, help the hot-head calm down. He was pretty sure he would get punched in the face in return but at least, it would allow his brother to blow off some steam…

_Last time, he hadn’t acted properly – according the common standard for this kind of situation, he lectured himself. His brother probably still resented him for that. But it wasn’t his fault if he couldn’t feel… things, the same way others felt them._

As soon as his hand touched the cold skin of his brother, Donatello mentally registering the feeling of scales under his fingers and preparing for the aftermath, Raph threw himself on him and hugged him with all his might.

« Oof ! » The muscular arms squizzed him too tight, threatening to suffocate him. He hadn’t expected this, but at least it was better than being knocked out, or thrown against the echograph.

Unless he lost consciousness from lack of air.

« Swear to me that you’ll help him… We need you, bro » He heard his brother whisper with a shaky breath, face pressed against the crevice of his neck. He even felt tears falling on his own skin.

A weird sensation for him who never had cried, not even once in his life.

He noticed that Raphael had called him « bro ». How long has it been since the last time they used pet names ? He couldn’t recall. His analytical mind told him that it was a good thing, allowing him to take control of the situation at hand. He knew he couldn’t reciprocate the hug without touching his brother’s shell, which would surely not be welcomed. It would r_uin the moment_, like they said ? So he just patted Raph’s arms again like he had intended to and, leaning back, gave him his best impression of a smile.

« Don’t worry. I’ve got this ». It was a lie, of course, but all things considered, his scientific mind was tingling. He had to get to the bottom of Mickey’s condition and formulate a reasonable explanation for what had happened, and maybe a solution – because it would certainly create some sort of handicap for a fighter like him.

Not to forget, the damage control regarding Leonardo’s response to this whole, fascinating mess.

Raphael didn’t say a word and brought him closer again, closing his eyes. They stayed like this for what felt like an eternity to Don. However his brother, while clinging to him, only wished to forget who he was talking to, what he knew about him, and believe there was still some kindness, and love, left in his genius brother.

If there ever was any.

**Notes for the Chapter:**

> First of all, thanks for reading my TMNT fanfic! Also, I'll be publishing, as much as possible, on a weekly basis (1 or 2 chapters) and add illustrations to the process. Next chapter will be enhanced with a couple pictures I especially drew for the fic trailer. I hope you'll enjoy! See you next Sunday :-)


	5. Consuming memories

**Summary for the Chapter:**

> Master Splinter and Leonardo go to the dojo to reach the astral plane and confront the Oni – engaging in a battle of minds and spirits, not the first of the kind. We learn more about the events that lead to the leader getting possessed, and the awful condition of Raphael…

« You must calm your mind, my son ».

The peaceful, composed voice of his sensei was reaching him from behind, even if he couldn’t see him or feel his presence.

It was like this now. Since that fateful night, when his fear for his brother had forced him to resort to desperate measures.

Gone was the beauty of the astral plane, when everything felt different, lighter, softer… And his flesh no longer weighed on his mind.

Now, he could only float in the darkness. This cage the demon had created for him was, of course, filled with traps and tools to break his mental health.

Despite all this, however, Leo’s spirit was strong enough to leave this secluded area where the Oni constantly tried to jail him, and travel through tortured, dead landscapes which pictured quite well what hell could look like. Along the way, his father was there to guide and support him throught this hardship.

This time, the shadows around him were relentless.

_Excited. _

He shivered when he felt how obscenely happy they seemed to be, like something great had just happened.

He could hear a faint rumor around him, voices whispering in the distance.

He knew he had to pass through this wall of darkness. Their motions made him feel a bit sick. But, as soon as he raised his hand to test their density, he felt – more than he heard – a breath of a voice tell him those words :

_« We feasted »._

And then repeat it again and again. The same two words, blowing in his ears like the wind, but with a malicious intent that left him shivering.

_What does that mean ?_

He had to remain in control of himself, and not give in to fear. He tried to push again the moving shadows, that looked like giant columns of black smoke, to make way. To his surprise, he went through them easily. And then he saw it. Pictures flashing through his mind like bullets, meant to hurt him.

Him walking in the sewers beside his youngest brother, looking at his shell which reflected his gaze partly.

The orange-banded turtle had made an habit of dressing up with a strange sheer ornament, which covered his shell and looked like glass – where it was really some kind of plastic, some « epoxy resin » according to Mickey – « kinda like sunglasses, but transparent and cooler! » Thanks to Donnie’s equipment, he had shaped a large piece of it so he could decorate his shell according to his artist name.

This, along with the paintings he adorned his body with – his so-called « homemade tattoos » -, were supposed to embody his art on his own figure, and give the young terrapin his uniqueness. At first, the leader had disputed the fact that it made the nunchaku-master a little too flashy for a ninja, when he was supposed to blend in with the shadows. Mickey had then sworn – while pouting ever so slightly – that he would never wear his « glass shell » in combat. Anyway, as far as Leo was concerned, the sea-green turtle was already unique on his own, and didn’t need anything else. He was the real sunshine of their life, and helped bring some color and joy in their otherwise gloomy home.

But the youngest wasn’t smiling anymore. In Leo’s mind, the scene of the Oni’s attack kept playing again and again. His brother trying to scream, obviously in pain. A spectral whirlwind entering his body and… Taking something ?

The leader suddenly found himself violently expelled from the wall of shadows. He fell on his shell and immediatley turned around to get up, his chest aching with pain. Trembling, he felt the dirt under his hand and closed his eyes.

In this realm, his pupils weren’t glowing. But no one was there to see him like he really was, like he should have stayed. He opened his eyes again and looked around.

It was the same ground as always. A lifeless, parched landscape, under a sky as empty as a black hole.

« Are you alright, Leonardo ? » the familiar voice felt like a blessing to him.

« Yes, Father ». His own voice was nothing more than a whisper, like the shadows behind him. Only Splinter managed to talk with ease, being outside the Oni territory. Still, he was able to reach his son, and it was no small feat.

As for the blue-clad turtle, he had to get going in order to reach the North-East Kimon, the demon gate, where he would be able to summon the Oni and fight him – again.

It always ended up like this : him fighting countless shadowy figures sent by the Demon, battling against an army of moving spectres, weakening his opponent one wraith after the other. Of course, the ninja didn't come out of it unscathed either ; each fight left him spiritually wounded, but also stronger. It was a necessary sacrifice, to be able to keep control over his own mind and body.

However, despite all his struggle, he had failed his family. He had failed to protect his youngest brother.

He wouldn’t let it happen again.

As he got up, he heard a voice behind him which wasn’t his father’s – and this time, not a whisper at all. More like an ominous growl.

He turned around and saw one of his others brothers. Raphael was standing in front of him, with a threatening attitude. His eyes were burning with pure hatred – something Leo never thought could happen, even in his darkest dreams.

The devil taking the appearance of his dear ones wasn’t anything new, but at least, most of the time he just had to fight shadows of his brothers – dark figures with a ray of color. Red, orange…

Purple…

This time, his so-called brother appeared quite solid, and no one could tell the difference really – except for those golden eyes shining with hostility.

Leo just knew Raphael would never resent him like this. But it didn’t mean it didn’t affect him, at least a bit.

« Not one step further », the clone said, posing between each word. Leonardo looked at him and saw his hands slide to his belt, and his sais.

It was a frightening good impression of his hot-blooded brother, but the leader didn’t flinch. He knew it was just another trick of the Oni.

« Go away. You’re not my brother », he just said, and turned around.

« How can your even say that to me ? Is that because of what I’ve become ?! » the katana-master froze. The tone of his opponent had changed. From pure violence, it had become desperate.

« So that’s how it’s going to be ? Maybe you forgot what happened…. Maybe I should show you again, so that you remember that you didn’t help me ! »

Leo felt the wind rise suddendly, which was unexpected. He had never felt anything like that in this cold, desolated area. In front of him, he saw something that looked like electric sparkles, tear up the dimension like a veil and open some sort of gate.

It all happened too quickly for him to react ; as soon as the path opened, he heard a roaring sound behind him and, as he turned around to counter the attack, he just had time to see the clone lunge at him and flat-hand hit his plastron, throwing them into the the whirling hole.

He was falling from an absurd height, but the closer he got to the ground, the more he understood where he was headed.

The research center. He should have known. He recognized the two tanks filled with this disgusting, fluorescent green liquid, and the circuitry around them. The movements in the second basin, indicating it was NOT empty, while the emerald-green turtle was about – he knew it – to take an unfortunate dive into the first one.

The Oni’s illusions felt stronger than ever. What could have make him so powerful, all of the sudden ?

_We feasted_.

Those dreadful words danced in Leo’s tortured mind. He couldn’t hear his father’s voice anymore. Juts those two words, echoing in his head. And then, he saw Raphael, who had fallen with him and gained momentum, go past him.

Gone was the animosity. Only remained the fear, the panic in his green eyes, while he looked at him with despair.

« Help me bro ! Don’t let me mutate! Save me! »

_« He will become a creature of nightmare »_ all around them, the shadows were back and chanting in deep voices, sometimes hitting a high pitch, like little girls.

Close to his ear slit, he heard a small voice say, in a sing-song tone : _« and there is nothing you can do about it »._

He turned around to look at a dark figure clinging to him, and smiling. He tried to get rid of it, only to see his hand go through it like he knew it would.

He had to keep control of himself. Never before had the demon had such a powerful hold on his mind. He felt torn from the inside, and it took everything he had not to give in to panic. He tried to focus his mind on the scene under them. The three of them were still falling together, even if in reality he was alone here, in the torments created by the Oni.

« It’s only an illusion », he tried to tell himself to regain some control over the situation, closing his eyes.

« Maybe you’re holding me responsible for this, Leo ? »

It was like time stood still. Like they were simply levitating in their current position, their mad fall interrupted.

This voice.

He opened his eyes to see his brother instead of the shadowy figure, however still holding tight on his shell, his trademark emotionless eyes on him.

« Of course you do. And you’re right, because, you know… » He pointed towards Raphael, and Leo could only follow his gesture and look at the poor soul falling down into the tank in a huge splash. « I didn’t help him back then… I didn’t even try to rescue him » Donnie’s clone continued, coming closer to the leader’s ear to whisper those horrible words, as the leader stared at the tank.

Drops of the thick liquid had flown all around – Raph wasn’t exactly light to begin with, and his fall had splashed all the devices around the pool. Maybe it had created some sort of electrical shorting, the leader couldn’t tell for sure.

He only knew what happened next.

A emerald green hand desperately tried to reach the edges of the pool, but the water – or whatever that liquid was – was already reacting and motioning around his body.

« Like I told you last time, this water, as you call it, is in fact an synthetic amniotic fluid, a very useful solvent for those types of experiments. » the clone continued, absolutely not bothered by the scene and seemingly able to read the poor katana-master’s mind.

« We wouldn’t be able to see the electrical reactions from this distance », Donatello’s clone went on, « I'll spare you the details, but it's a process involving electrolysis in the second tank, which is connected to the first one of course ».

For Heaven’s sake.

It sounded so much like HIM. Too much. Leo was starting to believe the Oni had been able to trap his real brother’s soul into his realm, and teleport him there with him.

« As you know, the second tank is filled with odonatas, those fascinating little carnivorous insects… And so, as in an anode and cathode system, the degraded dragonfly DNA flows through the connecting pipe to agglomerate with any creature present in the first basin. It is an incomparable feat in scientific terms, since it is a mechanical mutation, the first of the kind, using this fascinating substance and simple electrical currents close in intensity to those of the human body... »

Leo wasn’t listening anymore. He was just staring at the green pool, and listening to Raphael screaming like crazy, his head coming out of the water – only to get sucked back in.

« Of course, this process is nothing near neutral. The pain must be absolutely extreme. It is an atomic scale reconstruction of a living being on another living being after all ».

The clone’s ramblings barely reached him now. He had already heard it, in the same cold, analytic tone, while Raphael was lying down on the nursing bed, in the aftermath of this disaster.

The sai-master was conscious back then, unlike Mickey.

And he was crying. Leo could hear the muffled sounds he made, while burying his face in the pillow. He was in an excruciating pain, his shell now arboring the complete shape of a dragonfly. For someone like Raph, who completely abhorred bugs, it was the worst thing that could ever happen to him. An insect, embedded into his body, blending with his internal organs according to Donatello. The pain would not subside before weeks, and even so, the mental impact remained.

Leo couldn’t stand it back then, and he still couldn’t stand it now.

Back to his current predicament, the leader saw the poor soul finally able to rise from the tank, with bloodshot eyes, panting. It was obvious that the slightest movement caused him tremendous pain.

In reality, the katana-master and Mickey only managed to arrive at this exact moment, after getting rid of the gards, to find their brother cold and shivering, suffering like crazy, while Donatello just stood above the scene on a platform. They looked at him and couldn’t understand why he was like that, standing completely still, staring at them without saying a word. And then, rage took over and Michelangelo – yes, sweet, dear Mickey – started to yell at him.

« What the fuck Donnie ?! What are you doing up there, for fuck’s sake ? Get your ass down there at once and help us ! »

Leo had never heard his baby brother swear like that. He was red with anger, his big blue eyes darkened with grudge towards the genius. He could still remember the tone he used to address Donnie, a vociferation the leader wished he never heard in his little brother’s mouth. It was like the youngest had morphed into Raphael himself, since the once temperamental turtle had quit playing the hothead for now.

But here, in this sick simulation of the devil, there was no Mickey. Only Leo remained, along with this far-too-accurate depiction of his smartest brother.

Yes, Leo arrived only when Raph had managed to leave the tank. Too late to help him. Too late to save him.

_He hadn’t SEEN him struggle in the liquid while he was being… Mutated again. _

But now, he knew exactly how it looked like. It’s like he had been able to see through the eyes of Donatello, the one standing above the tanks, not batting an eye while his brother suffered a fate worse than death.

_« So, THIS is what you mortal wanted to set right ? »_

This voice.

This time, it was him.

The Oni.

Donatello’s clone had disappeared. In his place, stood the nightmarish vision of the demon, so much bigger than Leonardo, engulfing him in his red flammes. He could feel the heat, even if it was still bearable.

_« Such pitiful needs. You are no better than humans. Slaves to your primal emotions and attachments. Lesser creatures like you will never get what it is to have a superior existence and be free of mind _», the creature hissed between his fangs, staring at him with his giant, glowing eyes.

_« I even gave you my power, to what end ? You are immortal, yet you curl up on yourself like an abandoned newborn, clinging to other mortal creatures, crying over their fated death. Even if they become stronger, like this one _», he pointed at the red-clad clone still moaning in pain,_ « you still pity him, while he despises himself. Your flesh is so obsessed with trivial things such as… Appearance. And you are so pathetic that you want to be accepted by creatures so much weaker than you. Humans, who only managed to create a world sick with instability and __disequilibrium. All of this, while you could gain the upper hand and rule above them with my blessing ! »_

He leaned towards the poor turtle and snarled : _« This is why I despise you all. But your other brother… Is different »._

Leo felt a cold shiver run along his spine. He knew who he was refering too.

« Leave… Him… Alone ! » He yelled in the face of the Oni. He tried to reach for his katanas, but of course, they weren’t there. He had to create them with his mind, his own willpower.

_« Oh, do not worry little one, I will… For now »_ the Oni simply said. _« I must still gain power, and this one mutant is far too strong-minded for me to possess. You are weaker than him… Because of your feelings »._

Well, if Leo had any doubt regarding Donatello’s affinities with feels, it wasn’t the case anymore. However, the Oni could be lying, it wouldn’t be the first time either.

The forest-green turtle knew he could only rely on this small hope. He needed it desperately, right now.

The heat was starting to hurt him. He had to act quickly.

He thought about Mickey. What the Oni tried to do to him. How he saw him collapsed on the sewers ground.

_No longer moving._

That’s when the leader felt a powerful surge of rage. His desire for justice became so strong, it turned into a fiery blaze; Leo’s astral body then became engulfed in cerulean flammes, repelling the red ones of the Oni.

« Don’t you dare touch any of my brothers ever again ! » Two translucid katanas appeared in his hands and, when the devil had no other choice but to release his grip on Leo’s body, the leader slashed him with both weapons.

_« Strike at me and I will consume them to regain my power ! » _the demon roared.

« No, you won’t ! » Leo attacked his opponent again and this time, he could hear a deafening crashing sound, immediately followed by his father’s voice calling his name.

« Leonardo ! Leonardo, my son, are you alright? » His voice sounded deeply worried, and it was obvious the old rat was doing his best not to show his panic.

Around Leo, all illusions of his brothers and the research center had disappeared. He found himself lying on the floor of the dojo, his father hovering over him with anxious eyes. A sudden, and strong headache, made him growl.

« You returned », his father said while reaching out to help him get up. « I lost you during your meditation. I failed you. I am so sorry , my son… » Leo looked at the old sensei. His his heart tightened when he saw the pained and defeated expression on Splinter’s face.

« No, Father, you didn’t. The Oni trapped me into an illusion, one that looked incredibly real. He seemed far stronger than before… » the blue-banded turtle suddendly remembered what the demon had said about « consuming » his brothers.

_We feasted._

He jumped on his feet, despite feeling a bit light-headed and nauseous, and rushed to the door. Splinter looked at him with surprise.

« I need to speak to Donnie immediately ! »

In the meantime, said genius had been working in his lab, checking Mickey’s health state from time to time, while he was waiting for the blood results.

He felt a bit drained. The evening had been too eventful to his taste.

Looking around, he spotted Mickey’s bag, dropped by Raphael in a corner near the gurney. The red-clad turtle had left him alone after their « hug session » to blow off some steam with his punching bag, and leave the family’s doctor work in peace.

He grabbed the satchel and looked inside for the recorder. He had noticed that the device was still on when they arrived. Eventually, he had been unable to go back to the sewers to get some samples of the glowing goo left by the Oni. Maybe he could learn something useful if he listened to the recording instead ?

Shoot. The battery was drained. No wonder why, considering how long this thing had been running.

He didn’t know where to find the charger. Probably in Michelangelo’s room, however, he couldn’t just leave and go look for it. Raph would hear him and probably meddle in, demanding why he left the lab and their unconscious brother alone. So no, it wasn’t an option for now and he would have to wait. He didn’t want to ask the bulky turtle either ; he was glad he could be on his own for now.

Well, in the company of his youngest brother, but he was still out cold, so it didn’t count.

He left the recorder on his desk and went back to his computer. Looking at the clock above it, he wondered how long had it been since the eldest and their father left for the meditation session.

Probably an hour or so.

It was getting quite late, and since Mickey wasn’t available for now, it would probably be up to Raph or Splinter to prepare dinner. Donatello was ok with their sensei’s cooking, and Raph wasn’t too bad either. As for him, he was far too busy right now – bless the fact he was left alone to work. Just do not ask Leo about anything related to food, and everyone would be fine.

Said turtle suddendly opened the door – well, more like slammed it open – and barged in, which was quite unusual for him, Splinter on his heels.

_Talk about the dev… Hmmm nope. _

The genius could tell his brother was completely worked up, and didn’t look too good either. The meditation session probably didn’t go too well.

« Donnie, we need to talk ! What happened to Mickey ? I know the Oni did something to him ! »

And… Here it was. So long for having some quiet time.

The purple-banded turtle looked at their father, trying to gather all the support he could for what was about to come.

« Yes, Leo… I believe, however, that it would be better for you to sit down ».

He just hoped he wouldn’t need to jab the leader with a tranquilizer afterwards.

**Notes for the Chapter:**

> See Chapter 3 for a lovely art of Leo being possessed, by RabiaNoor on DeviantArt!


	6. Twisted feelings

**Summary for the Chapter:**

> Raphael explores the internet, trying to find a solution to get rid of the Oni, while Leonardo seeks answers from Donatello.

In his room, Raphael was looking for a solution on his laptop. It was a old model, with an exhausted keyboard and some keys indications missing – he had added some stickers with letters written on them to remedy this. The red-clad turtle couldn’t just tap from memory like the brainiac, after all.

He barely used his computer anyway. Just to look for workout music compilations and Youtube training videos… And some other things that would require that he cleans up his search history from time to time, knowing Mickey just loved to snoop around and somehow always managed to guess his password.

His heart tightened at the thought of his unconscious brother. He wanted to help him so desperately. Him, and Leo too. But what could he do on his own? He wasn’t any use against astral entities. As a matter of fact, he would even be a bother if he tried to meddle in the leader’s meditation session. Master Splinter often said that Raph’s spirit « wasn’t enough balanced », and that his shakras weren’t aligned at all – whatever that meant.

Of course, when it cames to emotions, Raph was well-known to be messed up. It even started at the root shakra itself, the first of them all, thanks to the anger that consumed him on a daily basis. Trust issues constantly gnawed at him, even towards his own brothers ; while at the same time, he found himself obsessed with ensuring his family’s safety. He felt like an essential foundation of their equilibrium, the first wall that should always shield them from external threats – at all cost. He could call them names all day long – bonehead, Fearless, brainiac… He still cared for them much more than for his own life. He was supposed to be the armor they should use to brace themselves against the world outside. The unflenching tower in a game of chess.

But he did a very poor job of playing gardian duty when it came to his outbursts of rage. Being so chaotic at the very core of his own self, how could he ever align his shakras ? How could he ever help Leo fight this terrible curse ?

The damnation the blue-banded turtle brought on himself because of _him_, Raphael, the insecure root which plagued their harmony as a family…

The sai-master shook his head. No time for self-pity. He needed to find something to help his brothers, and he needed it fast.

However, his search on the web wasn’t coming fruitful, and he was starting to get fairly annoyed. Chinese medical treaties mentioned various diseases caused by Onis in ancient times. Raph didn’t know how much of those recollections were true, if they simply were natural events and epidemics mistaken for curses, or real misdeeds of demons. But it didn't do anything to reassure him either.

They would be screwed if Leo fell sick, due to the influence of the Oni. First of all, he couldn’t imagine life without his eldest ; secondly, they needed him at his best, all the time. Being ninjas meant they were constantly fighting for their life, and couldn’t afford to lose one member of their team. Especially not their leader.

Donnie used to say that they were an « indivisible unit ». And, for once, Raph agreed with him whole-heartedly – though he would have chosen better words than some engineering vocabulary.

Raph may be the turmoil turtle, at least he wasn’t lacking that much in the heart shakra area.

While he was reading some excerpt of an e-book, he suddendly saw something that had him deeply concerned :

_Oni are often characterized by their cannibalism. _

Cannibalism… ? Did that mean this asshole of a demon would end up eating his brother ?!

He needed to get rid of this damn thing, right now !

Even if he had no idea how…

He had been researching the Setsubun, the celebration of the japanese New Year, where onis were expelled from houses using roasted beans. However, he doubted it would work on their leader, since the demon possessed him from _inside_…

Portraying his dear brother – a term he would never use out loud – being eaten alive, starting from the guts, made Raphael shiver. Just thinking of it made him feel sick.

Could the body be considered a house ? After all, it was home to the soul, so maybe they could try to « purify » it somehow…

Memories of old movies came to the emerald-skin turtle. They could try ablutions or sage fumigation maybe, like the amerindians. Or salted water. Their father had mentioned something like this at first, if Raphael remembered well.

The fact that the old rat didn’t act on it didn’t bode well for Leo. It meant that Splinter knew it would be no use, in his case.

The eldest would propably need a real exorcism, and this perspective was frightening.

The red-clad turtle wondered if he should print his findings, to have them at hand if needed. It wasn’t much to work with, but it was still a beginning. He even found some interesting books to order from the web. He would have to rely on April for the delivery, but she was always happy to help.

_Especially those days, when everyone tried to be useful, to make their life easier. They sure needed it. _

He saved the documents on an USB key and was about to leave his room to go back to the lab – the only place where they had an operational printer –, when he heard a huge ruckus coming from there.

It was Leo’s voice.

He rushed downstairs. He felt like he would never stop running to his brothers’ aid, if things went on like this.

« How is that even possible ! »

Leo was shaking Donnie with frenzy, the genius not particularly enjoying the rough treatment, while their father was trying to calm his eldest down. But the leader would not let go of the family doctor.

Tears of rage were pulling in the red glowing eyes, and Raph just knew the brainiac would NOT be able to find the words to appease the panicking turtle. In one swift jump, he joined them and, grabbing the katana-master, forced him to release his grip on the genius. He had to use all his strengh to do so ; Leo had never been weak to begin with, but the presence of the Oni made him significantly stronger.

He firmly pulled him back, nearly tumbling with his brother on the ground, save for Master Splinter grabbing them both and stopping their fall. Touching Raphael’s shell while doing so, which made said turtle shiver. He had to gather all his self-control, not to jump out of his father’s reach and to maintain his grip on his crazied brother.

_He just hoped his wings would not spread on instinct._

« Raph, let go ! » Leo yelled at him, struggling to break free.

« First you calm down ! What the hell is happening here ? You looked like you were about to rip the genius’ head off, and that would NOT be a smart move believe me ! » Raph barked at him, holding him tight.

« Well, thanks for your concern in my usefulness », muttered said turtle, while massaging his bruised shoulders.

Leonardo was indeed much, much stronger than before.

« I was explaining Mickey’s condition to him », he continued with an evened tone. Donnie was quite tired of his brothers’ emotional outbursts. But he understood how logical their reaction was, considering their predicament.

_Unfortunate, but unavoidable._

« How can he miss an organ ?! The Oni didn’t touch him ! You said I held him back ! » Leonardo yelled, trying to free himself from Raph’s strong embrace. However, even if it required much effort on his side, the bulky turtle didn’t bulge.

« Calm down bro ! Please ! There is nothing we can do for now, and if you get yourself in a full-blown panic, who knows what will happen ! » Raph shouted.

« Part of an organ », Donnie corrected with a sigh.

« He is right, Leonardo. You could lose control over the Oni », Splinter added.

_Lose control… Again._ The unspoken word rang into everyone’s ears like a silent accusation.

The heaviness of the realization struck the leader like a punch, putting an end to his struggle. Looking down, crimson eyes staring at the ground without seeing it, the leader collapsed into his brother’s welcoming arms.

Donatello looked at his two siblings hugging for the second time tonight, probably a breaking record since their childhood. Even so, Leonardo seemed to be constantly looking for some sort of support, and approval, from his family. Should it be their sensei, the hothead or even him.

Of course, it worsened after his possession ; the leader craved for comfort, probably living through countless nightmares and fighting every day for his own sanity, but didn’t dare ask for proximity. He was too afraid to hurt his loved ones, and oh so right he had been on this; tonight more than proved it.

However, against all common sense, he was now relying on their most temperamental brother to find some strengh. Maybe trusting his apparent robustness. It clearly was a terrible mistake, considering the way the Oni worked. Moreover, Donnie couldn’t help but think that relying so much on someone else, even a brother, would prove to be a weakness in the long term.

He, Donatello, was different.

« Is he in danger ? » Leo finally managed to ask, his lips shaking slightly. Even in this state, the katana-master’s voice remained strangely steady.

Bright, beautiful red eyes were staring at him and the genius cleared his voice. He still managed to get fascinated by the power emanating from them, but it was the worst timing to show it.

« I don’t think so », he replied while casting a glance at the sleeping turtle. It was fascinating, how the youngest could remain deep under despite all the commotion. But Mickey was known to be a heavy sleeper, so it wasn’t that worrying. « He will probably need some hormonal support, and I’ll have to check his blood results on a regular basis. Other than that, I don’t think he will experiment any discomfort ».

« Will he still be able to join us in our patrols… And train with us ? »

« We should take it slow for now, see if there is any side-effect to this. But I believe he will be alright », the scientist concluded.

Resting his head against his brother’s torso, Leonardo closed his eyes. Raphael could feel the leader’s heartbeat slow down a bit, after being in full panic mode.

« What can I do to stop this… I’m a danger to you all… »

« Stop this immediately ! », Raph interrupted him. Roughly grabbing him by the shoulders, he forced the blue-banded turtle to turn around and face him. « We will find a solution to this, together. Don’t you dare go away or do reckless things on your own ! I know you well, Fearless, and I’ll be behind you on every steps you take if I need to ! »

Leonardo stared into the golden orbs of his brother, burning with his well known feverish temper. The leader would not be able to negociate his way out of it, and he knew it.

« Your brother is right, my son. I won’t allow you to leave the lair and put yourself into even more danger. You need our support to fight against this demon ».

« What if I can’t control him, and he attacks Mickey again ? Or anyone else ? I won’t be able to live with it », Leo said in a pleading voice, trying to hide his face in his hands, disgusted by the contact of his horns. Raph grabbed his wrists and forced them down, and again, looked at him directly in the eyes. Golden green meeting crimson, glowing red.

« And don’t you dare thinking about ending yourself, brother. We are in this together, and we will do things together. You won’t be alone in this. Not anymore ».

« Also, if you died, the Oni would probably try to possess one of us instead », Donnie added.

Memories of the events in the astral plane came back to Leo, and he looked at his brother with wide eyes.

He didn’t want to think about this possibility.

Never.

« My son, you said the Oni had trapped you into some kind of dimensional prison. But you managed to break free. How did you achieve it ? »

Raphael raised an eye ridge.

« For real? »

« Yes », the leader said. « I… Was so angry at him. For what he had done to Mickey. I was able to strike at him… »

« Oh wow », the red-clad turtle said, pride dancing in his eyes. « But how ? »

« I often battle with him in the astral plane, but it’s like shadow fighting. I fight against spectral manifestations, with weapons I have to create with the power of my own mind ».

« That Oni plays dirty », Raph snarled.

« Demons are not known for their fairness », Donnie commented absent-mindedly. He had noticed that Mickey was beginning to wiggle on the gurney, and would probably wake up soon. Thus ignoring the hothead’s death stare at him, for his remark.

« However, this time I struck him directly. He was able to cast a solid manifestation of himself, inside his own realm. As soon as I hit him, I was free and able to come back here », the katana-master continued.

Their sensei looked like he was lost in his toughts, weighting on his son’s words. After a while, he said :

« You may have dealt him a heavy blow ».

« I believe so », Leo answered.

« Bro, that’s fantastic ! It means you can kick his ass, maybe even get rid of him ! » The emerald turtle was gleaming with hope. Leo looked at him, feeling even more guilty.

« Let us not put our hopes too high yet », Splinter simply said, and the eldest was grateful to him. « we still need to learn more, in order to set up our strategy ».

« The Oni said that if I weakened him too much, he would attack one of you in return », Leo gloomily said. « To regain his power ».

Silent fell on them, everyone turning their eyes to the daybed at the far corner. Mickey was slightly moving and moaning, not ready yet to awake. Leo was afraid he was in some kind of pain, while Raphael was too amazed by the possibility of having the Oni kicked out of his brother, and their life. It gave them some kind of hope, something they desperately needed right now.

And also, he couldn’t help but think that his eldest brother was a new kind of awesome, to be able to school such a powerful, demonic entity.

Meanwhile, Splinter was carefully watching his last son.

In the midst of everything happening, and judging by his various reactions since the beginning, the old rat had thought Donatello would only be worried for his own well-being ; but as surprising at it seemed, at this exact moment the olive turtle was wondering about his youngest brother and not himself.

It may be part of some kind of agenda, but still, it was a sight to behold.

The genius must have sensed something, since he turned his head to look at his father with curiosity.

« Yes, Sensei ? » he asked.

« Do you believe there is something we can do to revert Michelangelo’s condition ? » The wise rat enquired.

« As it stands, I don’t know. Obviously, the cause of his ailment is of the supernatural kind. However, I should be able to determine the nature of the physical process allowing for such result. It may help ».

« Very well ». With this, the old rat raised his hand.

« Leonardo, I believe you discovered a strong potential within yourself, one that could be the key to free your spirit from this possession. We need to explore this further, but not before we all have some rest, for I know you must be exhausted. I will prepare a light meal for us. That is all ».

« Someone mentioned food? » a sleepy, childlike voice rose in the darkness of the laboratory, and it sounded like the most beautiful sound to the mutant family.

Well, at least to three of them.

Mickey was stroking his eyes, looking like a baby owl.

« Yes, sleepy head ! Glad you’re still with us. You’re one tough dummy for resisting a demon’s attack », Raph said while walking up to him, trying to hide the shakiness of his limbs while he gave an affectionate smack to his brother’s head.

« Hey ! Don’t hit me dude ! » the youngest yelled playfully, trying to kick the bulky turtle with his feet in return.

« Take it easy… » Raph said, steadying him on the gurney.

He seemed just alright. Mickey was alright.

Leonardo breathed a sigh of relief.

« Ok, guys, so what happened and why did I sip some sewer’s puddle? » said turtle asked, while trying to get away from Raphael who nearly wrestled him to stay still. He also made a face when he looked at his arms, and saw that his « tattoos » had been all messed up by their forced bath in the foul water. He would have to clean and draw them all over again.

« I’ll brief you in », Donnie said while approaching the echograph. « You guys can go to the kitchen, we’ll join you in a moment ».

The three remaining fellows looked at each others hesitantly. Should they really rely on Donatello’s way with words to fill Mickey on his condition ?

« Better say it as it is », the genius added without looking at them, but he could hear their thoughts just right.

« Ok, we’ll leave you at it », Raph said. They couldn’t argue with this, and after all it was better for Michelangelo to hear it from someone not… _Too much_ emotionally shaken by the whole ordeal.

The emerald turtle suddendly remembered his USB key and, taking it out of his belt, he put it next to Donnie’s keyboard.

« Print those docs for me, will you ? I gathered things I could find on the web about exorcisms. It’s not much, but it can help. »

« Understood », the scientist replied. He had been so busy with his own things lately, he hadn’t thought of conducting those research himself. They had all been relying solely on their father, who was the more qualified to deal with supernatural things. But they could indeed learn something useful from the internet.

« You know bro… I feel peachy so… What’s up with my beautiful, slender body ? » Michelangelo felt a bit akward, being left alone with his… How to put it ?

_Freakiest brother ?_

Of course, the joking tone to lighten the mood fell flat on the brainiac.

« Mickey, I need you to take this seriously. And please don’t freak out too much either ; we barely managed to calm Leo down, if he hears you throw a tantrum, we’ll be back at square one ».

Now, the young DJ felt a bit scared.

« I’ll need you to tell me everything you remember about the attack, most importantly, what you felt at this exact moment. Did it hurt somewhere ? »

Michelangelo, trying his best to recall the event, started to tell his story.

« Hundred of voices in your head ? »

« More like millions, bro ! And it felt like Leo was yelling inside my brain too ! »

« Uh uh », the genius nodded, while taking notes.

« I also felt like being cooked to medium rare, because of his damn evil dragon breath », the sea-green turtle continued.

Donnie thought about the camera. Maybe it was the heat that got it, after all. However, his brother didn’t seem to have burns on his skin. He hoped it wasn’t some radioactive kind of wave, because he hadn’t thought of using a Geiger counter.

« And then ? »

« Then ? I kissed the pavement. »

« I see… »

He went to his desk to look for his detection device, while Mickey kept silent, flapping his feet under the bed. He couldn’t wait to be dismissed.

Donnie measured him just in case – he would have seen external changes already, if the youngest got irradiated. Then, he told him about his liver, showing the echograph and the black mass to his brother, who kept silent for a while, staring at the screen.

« Will it hurt ? » He simply asked. It was weird, but he was more worried about Leo than for himself. The guiltiness must have been strong with his older brother.

« Probably not, but you’ll probably have to take hormonal supplementation ».

« Hormowhat ? »

« Don’t worry, I’ll take care of the technical aspects. You focus on your health and you keep me updated if you feel anything strange ».

With this, the genius was about to gesture the door to his orange-banded brother, but stopped right in time.

He had to keep a comforting image, at least for now.

« I believe you can stand up. If you’re feeling ok, you can join the others for dinner. I’ll be there soon », he simply said.

Mickey was relieved to leave the laboratory, even more now that he could smell an appetizing smell coming from outside. He was famished ; probably the backlash of his fainting.

However, he stopped before exiting the room, and turning back, said : « Who did bring me back here ? Was it Raph ? »

« Raph was carrying Leo, who had fainted too. I carried you », the genius answered absent-mindedly, while typing on his computer.

Mickey couldn’t believe what he had just heard. The brainiac _carried_ him to the lair ?! He, who didn’t seem to care about anyone but himself ? Sure, he helped them in combat and always took care of their injuries, but he clearly did it out of necessity, in the coldest manner. This time, he could have left Raph deal with it on his own. But he _did_ help ?

Suddendly, Donatello was tackled from behind by an overjoyed Mickey who – to his utter abhorrence - nuzzled into his neck and said excitedly:

« Thank you so much bro ! I knew you had a heart somewhere! »

One more hug, and the genius could have barfed. He was glad Leo was satisfied with Raph’s arms earlier, and didn’t feel like embracing him too.

« Yeah you’re welcome, now please go, I have work to do », he said while trying to break free from his clinging brother.

Said turtle finally let go and happily bounced out of the lab.

Donnie felt like barricading himself in his refuge.

He had enough of his brothers for this evening. Enough of this so-called _bonding time_.

_So long for dinner._


	7. Story illustrations: Trailer

**Summary for the Chapter:**

> No story! - Here are the brothers like I drew them for this fanfiction. Each one has his own font to reflect their alternate universe personality.
> 
> NB : I’ve been warned that the pictures do NOT appear on Ipads. Do you have this problem too ? They are hosted on my personal website and if it’s the same for you, I may have to find a better place to stock them.
> 
> UPDATE: I've changed website and the pictures are appearing now (at least on my tablet). I hope you can see them :-)

You can follow me on [Instagram](https://www.instagram.com/chemistryofadream/) or visit my page on [Deviantart](https://www.deviantart.com/chemistryofadream) to see all my illustrations :-)

**Notes for the Chapter:**

> I found a job :-) it's great but it means I won't be able to write and draw as much as I was used to. However, I'll try to keep publishing at least 1 chapter a week (because me want to know how the story goes too)!


	8. The Devil call

**Summary for the Chapter:**

> Raphael plays the night sentinel, while Donatello manages to listen to the recording of the incident in the sewers…

Everything was quiet in the lair. Three turtles and one rat had separated to go to their respective rooms, and try to catch some sleep – however, Raphael couldn’t help but get up to check on his youngest and eldest brothers. The first one was sleeping soundly, with a goofy face, like nothing had happened. At least, he had remembered to remove his « glass shell" thingie, and had even showered.

More suprinsingly, Leo seemed to sleep peacefully too, breathing evenly. The bulky turtle was impressed, and really hopeful. Quietly, he closed the door, a smile on his face.

It was the first time he saw the leader sleep so well, since the night he got possessed. Raph knew it for sure, since he had made an habit of checking on his family after bed time. He always had a hard time watching his brother roll and turn in his bed, pearls of sweat on his forehead while he was fighting some nightmare off. Sometimes, he even moaned in pain, and it tore the sai-master heart out to see him in that state.

But not tonight, the emerald turtle thought, deeply relieved, going to his father’s door to check on his sleep too. He wouldn’t dare open the wood panel, though ; he just wanted to listen carefully, in order to catch any unusual sound. Satisfied after a while, he took a look downstairs.

Of course, the brainiac was still working in his laboratory, and the door was locked.

The red-clad turtle didn’t mind, for once. After all, the family doctor had a lot of research to do regarding Mickey’s health. But he hadn’t joined them for dinner either ; maybe Raph should fix him a quick meal and bring it to him ?

Raph was so thrilled with Leo’s abilities to kick demons’ butts, he felt like being nice to his other brother. It even seemed like the leader had gotten the devil good this time. If only he could bulldoze him to oblivion, and also force him to bring Mickey’s liver to his normal size again…

Approaching the kitchen, Raph heard something coming from the lab. It sounded like… Opera. Tortured violins releasing gusts of jerky notes in the middle of the night, between high and low notes. Followed immediately by the deep sound of the contrabass, and a lonely piano crying over the dark, yet intense melody.

Indeed, their nerdy brother loved to listen to classical music. It helped him focus, he said. However, his choices were rather… How to put it…

Dark.

Raph went to the fridge and opened it, looking for some butter and ham to make a quick dinner. Maybe he would indulge in some midnight snack too… He hadn’t eaten much earlier, too excited to hear again about the fight between his brother and the Oni. But Leo wasn’t so kin on providing more details ; he just said that the demon reminded him of the recent event at the research center.

The bulky turtle had repressed a shiver.

How could HE ever forget ?

Suddendly it hit him ; what Donnie was listening too.

Batman soundtrack. Probably some ambient music about Arkham city, the place where they gathered all the merry crazy criminals of Gotham.

All the evil geniuses too.

Raphael used to believe that his brother could have belonged there too. Especially on this grim night back then, where his life changed forever.

Suddendly, he felt a little too tight in his shell. It had been some time since he had… Released his wings.

Nervously, he looked around in the darkness surrending him, making sure no one had followed him. It was stupid of course, he had just checked on his sleeping brothers and father, but still.

He hated to make a show. He despised those membranous wings he had acquiered after his second mutation, along with a complete body of a dragonfly, merged inside his own shell, and covered with keratin like his scutes. It even had the same color.

Mickey used to say that it was like a work of art, and that it looked kind of beautiful. Raph would have punched him for this, if he hadn’t known the youngest only tried to lighten his mood and bring some positive side in this. As for the brainiac, he had pretended that, should the emerald turtle be able to use his new wings, Raphael would gain a considerable tactic advantage over their enemy.

Fly. Would he even be able to use them this way ?

The organ had replaced the violins, resonating slightly in the corridors. Raph hoped that it would not wake up their ear-sensitive father. Maybe he should ask Donnie to tone it down a bit.

He really felt uneasy now. He had to spread his wings, even for a short time. Putting down the plate with the ingredients on the table, he left the kitchen and went to the living room.

He needed some room to be able to get them out.

He was starting to shake a bit. Breathing deeply to calm down, he straightened himself up and concentrated on his back.

Then he heard it.

That caracteristical sound they made, when the first cover, made of hard material, moved out of the way, on each side of his shell.

Then the wings came out, and from the corner of the eye, he could see their bright, orange-red color.

_Sympetrum fonscolombii_, Donnie said. The Red-Veined Darter. Yes, it was rather a cool name, for a digusting bug that had taken shelter inside of his organs. At least, the genius was positive that it had been a male specimen.

Raph would have committed suicide if this thing began to lay eggs inside his body. However, according to the scientist, it would not be possible either way ; the bug wasn’t exactly alive to begin with. It only performed his vital functions thanks to the sai-master himself. It was like a working exosqueleton, but its DNA had been reconstructed on Raph’s own ones.

This is the main reason why it couldn’t be removed. That, and the fact that it completely permeated his insides.

It was also the reason why Leo had sought the help of a demon, believing he could bargain with him for his brother’s salvation. What was the price the leader was willing to pay, in order to help him ? Raph saw red when he heard about this. Even more when he saw his brother get possessed by a spirit far stronger than him, without even granting his request. The Oni didn't give a damn for mortals’ miseries ; he was only seeking to interfere into the physical plane, and wreck havoc on Earth, using Leonardo as his flesh puppet.

Raph had shed many tears of rage over all this. He couldn’t help but feel responsible for all this mess. If only he hadn’t fallen into this tank.

_He just wanted to help. To save his fucking brother, who had managed – again – to put himself into a dangerous situation. When the sai-master arrived, he saw the genius fight against at least five guards, on a plateform above the tanks. They had weapons and were fighting dirty, trying to tear him into pieces. They were yelling like crazy, saying « one of the professors’ experiments had broken loose again », like if Donnie was some kind of lab freak. _

_The genius didn’t seem to mind the name calling, though ; he was more focused on the fact hat two of them had riffles, and were trying to aim at his head without gunning their colleagues down. _

_Raph entered the melee and took two of them out, evening the odds. They were used to battle against dozen of ninjas, but guns were another thing. A quick spin and a uppercut on the jaw brought another one to sleep. Only two left, but those were the trickiest ones. They were trying to wrestle Donnie down. And it looked like the ninja turtle had a hard time getting rid of them. _

_Suddendly, Raph had saw a small dart syringue on the floor._

_Those assholes had used a dart gun on his brother ! Now he understood why the genius seemed so much slowed down. Even so, he had managed to keep them at bay until now. The red-banded turtle needed to help him get rid of the remaining foes._

_He jumped into battle and, grabbing the first one by the throat, tossed him several meters away. He was about to kick the other one, _ _who was still fighting his brother, with a _ _geri kudaki, when suddendly, Donnie fell on him from behind, hitting his shell and making him fall over the safety rail of the platform. He couldn’t even grasp what was happening before he entered the green, fluorescent water. He remembered that it tasted salty and ferruginous, like blood diluted with sea water._

_And then… It happened. _

_All the while, Donnie was watching. The remaining guard had dived too, probably tossed by the turtle, but was unfortunate enough to hit the ground instead. He wasn’t moving anymore, and later Raph found out that he had broken his neck. _

_Raph would have given everything to be the one hitting the floor. It wasn’t like this simple fall would have killed a mutant turtle like him ; he was far too robust for it. _

_No, he had to dive into that fucking basin, and become an even weirder freak of nature than he already was. _

_While Donnie was watching, not doing anything._

Maybe it was the sedative still messing with his reactions ; maybe it was the shock of seeing what was happening to his brother.

Yeah, no. Raph’s vote went to the induced sluggishness.

After that, his brothers had arrived, while he was screaming his guts out. Breaking into tears, as Leo tried to help him get up. Mickey trying to find a way to reach Donatello, who was still on this damn platform.

Raphael had heard a slapping sound coming from above.

Mickey had hit the brainiac. It was one way to help him come to his senses. After that, they left in a hurry, to avoid attracting more guards.

The next days had been horrible. He was still in a great deal of pain, while Leo was going around in circles, trying to find a solution to help his brother. The leader also lectured Donatello on multiple occasions, reminding him that he should never have gone to this high-security facility without them. Heck, without even telling them of his plans !

He had lied to them, said he would go for a short scavenging trip to the nearby junkyard.

How many times had Donnie kept the truth from them ? It would explain a lot, considering the strange drugs he managed to acquire and stock in his lab. Even some devices looked out of place, more made for torture than real medicine. He always dismissed the strangeness of this all by using the « research » excuse, or the « scientific interest ». It didn’t sound convincing at all, nor reassuring.

They all knew how their brother’s mind worked.

It was like that with Donatello : always on the verge of doing something they couldn’t forgive. Always dancing on the fine line of what was morally admissible, nearly crossing the boundaries, to finally back down under his family’s pressure.

A devil in his own ways.

Absent-mindedly, Raphael flapped his wings.

Mickey said that they were magnificient, harboring colors so bright, almost iridescent, that they looked like small pieces of the sunset sky. With his artistic mind, he always said he wanted to draw a portrait of the sai-master spreading them.

Out of the question.

Raphael hated what he had become. He just managed to hide it better those days, because of Leo’s condition.

What he couldn’t stand, was when the brainiac tried to make fun of him. Like… Just before the Oni attacked.

After remembering all this, Raph didn’t feel so much like being nice to the family doctor anymore. But it was his duty to make sure everyone was fine.

It was time to close his wings. The soft silky sound of them retreating into his shell made him shiver. After making sure the hard shields were folded back on the top, he made his way back to the kitchen.

**Meanwhile, in the lab…**

Donatello had managed to find a suitable adaptator, and charge the recorder’s battery. The music helped him to avoid falling asleep, while he was printing Raph’s documents and looking at Mickey’s blood results.

For now, everything seemed normal. As for the echograph, he was calculating the mass of the liver, taking his own organ as a reference control since he didn’t know how much Mickey’s one weighted before the shrinking.

He was trying to calculate the coefficient for hormone metabolism, when a quick glance at the recorder’s battery showed him it was full.

_Nice._

He lowered the music, grabbed a headset and, placing the device on his desk, he pressed the listening button.

At first, he only heard Mickey’s attempts to get a good rendering of the water drops.

« Crap ! I forgot my headphones », his brother said in a pout. « No big deal, I’ll check when we get back. I’m sure I’ll catch some good sounds for my library ! »

Another regular sound, probably the one of their footsteps on the wet ground.

« I’m glad you came with me bro ! Isn’t it exciting ? You’ll see what I can do with those natural effects. You’ll be the first one to hear my next composition ! » the words were muffled, but still recognizable.

_I bet Leo was looking forward to it_, Donatello thought with a sarcastic grin.

Then, he heard something else.

_You shall come to me… _

He wasn’t sure he had heard well.

He was about to listen to this part again, when he heard a knock on the door.

« What now ? » he said out loud, slightly exasperated, putting the headset down.

A voice answered from behind the closed entrance.

« It’s just me, bro. I brought you some dinner. You didn’t eat with us, so I thought you would need some fuel to make that big brain of yours function properly ».

The last thing Donnie wanted right now, was to spend time with his hotblooded brother.

« Thank you, but I’m not hungry » he replied, trying to get rid of his visitor. « You should be sleeping, it’s really late », he added, looking at the clock.

« Same to you, brainiac. I know you’re in full scientist mode, however you won’t be able to do much if you fry your brain with sleep deprivation », he heard back.

« I’ll take a nap in the daybed », he said dismissively.

« You should still eat. Come on bro, I made it especially for you ».

Sighting, Donnie went to the door and opened it. The faster he would take the delivery, the quicker Raph would leave him alone.

« It’s just a sandwich », he said while eyeing the plate.

« But made with love », Raph retorted with a smirk. « By the way, it’s great you turned down the music, I don’t want Dad to wake up ».

« You’re welcome. Now, can I get back to work ? »

« Yeah, yeah. Don’t forget to have some shut eyes too », the bulky turte said while shoving the plate in his brother’s hands.

Donnie answered by closing the door shut again. Not slamming it though, to avoid waking up other pesky, concerned family members.

Back to the recorder.

He put the headphone back and listened again. He couldn’t help but feel excited.

Eager, even.

« … my next composition ! » « ... _You shall come to me _».

He had heard right. And it wasn’t his brother’s voice either, nor Leo’s. This one talked in a deep tone, almost like a whisper, which somehow resonated in his ears.

It could only be the Oni. The purple-banded turtle let the recorder play the sequence further.

_I know of your thoughts… Of your dreams… Of your quest for power… _

Suddendly, Mickey’s voice interrupted the other one :

« Here ! It looks like a good spot ! Come on Leo ! »

Splash sounds. Small steps towards something, probably a pipe on the wall.

_You are much stronger than your brothers… But not strong enough yet… _

Donnie didn’t understand. It felt like the Oni was talking to him, like he knew the genius would be listening to the recording at some time or another.

_I can help you become a god among insects… You just have to welcome me…_

Donatello removed the headset and looked at the recorder in dismay. Was it a trick of the demon ? Probably.

But still…

_I can help you become a god among insects._

He felt those words echoing through his mind, again and again.

Of course, he had thought of it many times. But he didn’t want to bargain power, should it be godlike, with his own soul.

But did he even have a soul ? Did they, as mutants, have a hope for an afterlife ? Or were they accidental existences, pure emanations of nature, bound to completely disappear with their death ?

He had never given much thought to those metaphysic questions, more interested in the physicality of things, and what science could verify and prove. Still, it was a valid concern.

Did he even have anything to bargain with ? Of course, they seemed to have an astral body, since Leo managed to travel through dimensions with it. It wasn’t a guarantee for having a soul, however.

But they knew the Oni was only interested in entering the physical plan, not in damning people. Any host would do, souless or not.

_Fascinating._

Donatello didn’t even noticed he had put the headphones back. Listening to this guttural voice once again, staring at the clock above his desk without seeing it.

_Come to me…_

After a while, Donatello began to feel something was off. He could tell it was already late in the human day, and the time would come soon when his brothers would wake up.

But the clock didn’t seem to be moving… Was it broken again ?

He had a strange feeling about it. He looked at his computer’s screen to confirm his doubts, however, it was nowhere to be seen.

He found himself in the middle of nowhere. Even the headphones had disappeared. Only he remained, sitting on what looked like a rock – instead of his chair.

Flabbergast, he looked around and saw he was in some kind of deserted land.

A dream ?

He must have fallen asleep on his desk, while listening to the recording. This strange, deep voice probably triggered some hypnotic effect.

Damn, he should have been more careful. Just because the Oni seemed to be weakened by Leo’s attack, didn’t mean they should let their guard down.

The genius got up, getting used to the strange feeling of the sandy ground under his feet. He wasn’t cold, nor warm ; but the absolute silence around him was nearly deafening. What should he do to be able to wake up ? It looked awfully like what their leader had described earlier, about his previous trips to the astral plane.

The demon’s realm. If Donnie’s spirit had been teleported there, he didn’t have much of a fighting chance. He wasn’t nearly as good, as an etheral warrior, as Leonardo ; he would probably not even be able to equip himself with his bo.

Back in the lair, Leo was in a deep slumber, recovering from the last battle. With great relief, he noticed he was only having mundane dreams about his everyday life. Playing ninja tag with Mickey. Sparring with Raph. Training under Splinter’s supervision…

While he was dreaming about repeating some katas in the dojo, he suddendly felt a gust of wind on his face.

It felt awfully familiar to what he had experimented in the astral plane.

Looking around, he wasn’t surprised to see that he was somehow back in the deserted land. Gone was the tatami floor and the old paper billboards harboring kanjis ; he recognized the tortured landscape and the void above his head.

Had the Oni already recovered ?

_Wait._

There was someone else there.

Focusing on the silhouette in the distance, he recognized Donatello’s clone, who had tortured him earlier with those awful memories. Again, he was pretty solid, turning his shell on him like he wasn’t aware of his presence.

This time, the forest-green turtle would NOT let this devious demon play with his mind. He knew he had the upper hand. He would crush him, no matter how he looked like.

Two katanas appeared in his hand, as he approached his target in complete silence.


	9. What if? (Part 1)

**Summary for the Chapter:**

> Interlude ! what if Mickey had chosen Raph instead of Leo to go sound hunting ?
> 
> A little fantasy in two parts, involving alternate storylines, and humor (who said comic relief ?) You can skip it if you prefer to follow the main story.

**Back to Chapter 1...**

  


The young turtle reflected on his options.

He considered asking Leonardo first, but heard a sound in the nearby room. Raphael was punching his bag, like the nunchaku-master thought he would.

He couldn’t help but feeling like bothering his favorite hothead a bit. After all, with his current condition, he was so depressed, he needed some distraction! and what better way than having his marvelous, funny DJ of a brother come to his aid and offer an adventure in the sewers?

  


His choice made, Mickey jumped out of the bed, landing gracefully on his old, tattered – and copiously stained – carpet. Catching his bag on the way out, he slipped the recorder and mic into it. He was pleased to see he had already put the backup battery in the front pocket ; whistling contently, he left his room to go to Raphael’s door, and pondered if he should knock or simply open it.

The old « keep out ! » sign Raph had put on it wasn’t exactly an invitation either.

  


Muffled sounds of regular hits could be heard behind the closed planel, along with some trademark grunting and panting. The orange-banded turtle was pretty sure the place would stink like a quatterback locker room, so he mentally prepared to be to be assaulted by the musky sweat smells that defined his bulky brother.

Maybe he should just pinch his nose ? But it wouldn’t work in his favour, especially when he wanted to ask something from Raph. So he just knocked – not willing to alienate the temperamental brother – and, big effort for him, waited for an answer.

He even had to knock twice, before hearing an unwelcoming « what ! » barked in the distance.

_Great._

For a second, the young DJ wondered if he should simply abort the whole deal and go look for Leonardo instead. But he gathered some courage and opened the door. Immediately, his nostrils filled with Raph’s intense bodily smell, and he made a face.

« Man, it stinks like a doghouse here ! You should ask Donnie for some additionnal ventilation, sewers air wouldn’t be as bad… »

_What an introduction ! Way to go Mickey,_ thought the young turtle.

« Yeah ? Well, good you’re here, my punching bag was starting to give in » said Raph in a menacing, yet still jokeful tone, while steadying said bag and turning around to face his visitor, clenching his fists.

« Nah bro, I’m good », Mickey answered, trying not to get cornered against the door frame while Raph was coming closer, an evil smirk on his face.

Maybe he should just run away and look for Leo, after all. Or barricade himself in his room and wait for the hothead to calm down.

« Oh no you’re not. What did you say about this smell of mine ? » With no warning, he plunged at Michelangelo and ippon seoi nage-d him, projecting him on his bed like a rag doll. He then proceeded to wrestle him down before Mickey could even react, the youngest caught in his thick left arm in a stranglehold position.

« So what do you say now, bonehead ?! Happy to be able to smell it from up close ?! »

« Urgh, Raph ! Lemme go ! » Mickey yelled, trying to break free from the death grip, to his big brother’s amusement.

« I’m not sure I heard an apology yet… » Raph said. He obviously was enjoying himself, torturing his poor, delicate flower of a brother, Mickey thought, starting to feel really uncomfortable.

« Sorry, I’m sorry ok ! »

  


« Good. Do you yeld, by the way ? »

« Yes I yeld, I yeld for shell’s sake ! Let go ! »

« Fine », Raph said, releasing his youngest brother. Mickey rolled out of the bed immediately and got up to face the emerald turtle, who was smiling widely.

« You’re such a douche, you know that ? »

  


« Proud to be. So what did you want ? I guess you didn’t come here to get your ass beaten right ? »

« As if ! I let you win! »

« Yeah right », the sai-master answered, looking for a towel to wipe off the sweat he was covered in. As for Micket, he sniffed his body with disgust ; he was sporting a nice, strong Raph perfume now.

« Thanks for the stink, now I’ll have to shower. So yeah, I was about to ask you if you would like to join me in a little trip in the sewers. I want to go sound hunting », he said, motioning at his bag which had fallen in a corner thanks to their little judo session. At least, Mickey was careful enough to put it on the ground before flying in the air.

« Sound hunting eh ? » Raph answered, tossing the towel on his drums.

« Why not. Just let me wash first »

Mickey didn’t like the sound of it. The bulky turtle was known for enjoying nice, long showers and consequently emptying their hot water supply.

« No need, dude ! Come on, it’s a trip in the sewers, not a gala dinner ! And your stink will help keep rats away, now that I’m wearing it too », he added.

He really couldn’t help it. He just loved poking at his older brother.

They all needed some light-hearted humor, after all. Michelangelo had noticed that, from the beginning, Raph had avoided turning his back to him, and the nunchaku-master knew just why. But he wasn’t about to highlight it.

He had tried many times to convince him his shell was nothing to be ashamed of, but it was a lost cause.

« Seems like you enjoy being used for boxing practice », Raph replied. « Fine, let’s go. I’m tired and I need a shower, and it makes me kranky. You don’t want me kranky».

« Sure thing, bro ! » Mickey was delighted. It had been a long time since he had an opportunity to spend alone time with one of his brothers. Because of what had happened, Master Splinter had forbidden them to go anywhere alone. They were supposed to do all their activities together, which amounted to training and patrol, and then each turtle go about his own business. No more bonding time, no more playing around together. Just some kind of daily reality where they were constantly reminded they could die at any given time, and should be prepared.

In a word, it sucked. Big time.

But he, Michelangelo, would change this dynamic and help his family get out of this vicious spiral !

Or at least, he would try to.

Mickey grabbed his satchel and they went downstairs, right when Leonardo and Splinter were leaving the dojo.

« Where are you going, my sons ? » their father asked, a small hint of concern in his eyes.

« Sound hunting, Sensei ! Don’t worry, we’ll be really quick. I just need to catch some mix-worthy sewer’s drop sound! »

The old rat shook his head. He had no idea what it meant.

« Very well, but don’t be gone for too long. We will soon have dinner. »

« Gotcha ! » Mickey answered. He was overjoyed, so happy he didn’t notice the way Leonardo looked at him.

With his crimson, glowing red eyes.

Touching his blue horns absent-mindedly, while casting a sad glance at his brothers as they were leaving the lair.

Right at the entrance, however, Mickey felt his gaze on him and turned around, to see his eldest standing there, not quite sure what to do. They were just in front of the laboratory, which door was closed. Their genius brother was probably caught with some project of his own.

_Good._

« Yo Leo… Wanna tag along ? » the orange-banded turtle asked with a smile.

_Two brothers_, Mickey thought ?_ It was bonding time alright !_

« No, thanks… I’ll… I’ll be in my room », the leader answered hesitantly, then, with a defeated sigh, turned his back to them and left in direction of the stairs.

« Mickey, you’re coming or what ?! » said turtle heard behind him.

Michelangelo shrug his shoulders, and left with the sai-master.

He just hoped Leo would not end up being the one on dinner’s duty… His stomac would probably not be able to handle it.

However, their conversation had been heard behind the doors of the laboratory. And someone was now looking at the pictures of the various cameras placed in the sewers, following his brothers’ progression in the undergound maze.

  


_Raphael’s shell from behind. What a sight to see !_

He knew he wouldn’t be interrupted. Master Splinter was probably already watching his soaps in the living room, while Leo would be somewhere trying to kill time and keep his mind busy.

Donatello could get the reason why. But he couldn’t help but think it awfully looked like some exclusive self-pity parties the leader constantly threw for himself. Yes, being possessed seemed unfortunate, but if only their eldest was able to see the bright side of this… The power… The immortality…

As he watched the various screens opened on his computer, something red and gleamering caught his attention in the corner, and he looked, amazed, at the scene unfolding before his eyes.

« Mickey, for fuck’s sake ! What are you doing ! »

  


« Calm down bro ! I didn’t know they would spread on contact ! How come you’re so sensitive now ?! »

« Sensitive ? SENSITIVE ? Try having a damn bug clinging to your internal organs and we’ll talk again ! »

Raph’s wings were so big, they were filling the sewers tunnel completely. Mickey couldn’t help but think that it was the most beautiful thing he had ever seen, even in the dim light of his pocket torch. Being translucid despite their intense, red color, they reflected the light like his own decorative « glass » shell. He was even a bit envious, now that he was able to see them from up close.

« Damn it ! Now I have to bring them back in again ! »

« Does it hurt ? » Mickey asked, just to be sure.

« No it don’t, but the feel of it, it sucks, you know ? Like having extraparts you can’t control. I hate this… » Raph answered, concentrating on his back to fold the wings. Their membranes were really thick. The reason why, according to the brainiac, was because they adapted to turtle mass, in order to allow the sai-master, should he want to, to use them to fly.

However, pigs would fly themselves before he tries to !

« You know Raph, they look really good on you… »

« Don’t even go there », he snapped at Mickey, still trying to control his wings which were beginning to flap uncontrollably. They needed to find an open area.

Fortunately, they arrived at a rather large crossroad, and looking above, Raph saw it was some kind of wide conduit reaching the surface. Perfect.

« Uh, Raph ? »

« What now ! » he yelled, turning on himself to gain some control over his « extra parts ». He was bouncing all over the place now, and suddendly, he found himself standing on a pipe, several meters above the ground.

He didn’t remember jumping over there.

« Did you just… fly ? »

Raph kept silent for a second, staring at his youngest brother down below.

  


« … Well shit. »


	10. What if? (Part 2)

**Summary for the Chapter:**

> What if Mickey had chosen Donatello instead of Leo to go sound hunting ?
> 
> A little fantasy in two parts, involving alternate storylines, and humor (who said comic relief ?) You can skip it if you prefer to follow the main story!

_I immediately regret this decision_, the yound DJ thought. He was holding his recording device, following his genius brother who looked delighted.

« I’m still impressed you decided to ask me instead of Raph, or Leo », Donnie said, probably smirking, not bothering to turn around to look at his brother while speaking.

« Yeah… Sure thing bro », Mickey said in a hesitant tone.

_Why, oh why ? What made him think it would be a good idea to be left alone with Donatello, of all turtles, in those gloomy, deserted tunnels ?!_

It looked too much like an horror film scenery. The tunnels swallowed in darkness, the October’s coldness and the strange sounds all around them while they were walking…

Wait, he was there to record drop sounds, right ? He nearly forgot. He didn’t want to admit it, but he was kinda… Scared.

Not yet terrified, but still.

So, he had joined the scientist in his own lair – the laboratory – in order to ask him a bit of his time to join in the small trip to the sewers. Why did he do that, again ?

He had thought of asking Raph first, but his door was closed shut and he didn’t answer when Mickey knocked. Twice.

As for Leo, he was still barricaded in the dojo with their father when they left.

Even so… He could have waited for the leader. Heck, he could have called April, or even picked up the lock of Raph’s room, for turtle’s sake ! Why did he go to their nerdy, evil genius of a brother, who was enjoying himself way too much right now ?

« After all, who knows what could happen… It seems like we are now forbidden from doing anything interesting, in case we run into trouble… Thanks to Sensei », said turtle said, probably still smiling.

« Come on Donnie, don’t be like that. It’s to protect us, after all that… Happened », Mickey answered in a small voice, pouting a bit.

It was rich, coming from Donnie. Running into trouble – even causing it – was his forte after all, and the triggering event for the whole mess they were in now.

_He should just shut up_, was what Mickey thought.

« Now now, where’s your small talk, brother », the genius mused, turning around and looking at Mickey – somewhow _fiercely_, despite his smile.

Brown irises, with a touch of red, were staring right at baby blue eyes.

Mickey averted his gaze, lowering his head. He felt awkward, and suddendly he only wished to come back home and put some distance between him and Donnie.

« I thought it was some kind of bonding time you know… » the genius said in a soft voice, coming closer to him. « You’re not even using your recorder… »

« Yeah, I don’t know, not like there is much interesting sound around… Maybe we should just come back… » Mickey tried, refusing to look at his brother who was invading his personal space slowly.

« Already… ? Come on, we just left. I want to spend some quality time with my younger sibling », he said, laying a hand on the young DJ’s shoulder, sending a shiver through his spine.

« Ah yes, ok, let’s try to record something » Mickey said, trying not to flee the contact on his skin. Donnie’s hand was incredibly cold, even for a reptile.

Actually, the sea-green turtle wanted to believe that Donnie was trying his best to be nice to him. After all, he had tagged along, not even hesitating one bit.

It was just really hard for Mickey to think that way, when it came to the purple-banded turtle.

Mickey tried to smile – which came a bit lip-shaky, but close enough – and walked to the pipes on the opposite wall, while Donnie stood in the centre of the tunnel, seemingly on watch duty.

« Playing the sentinel here, Don ? » Mickey asked in a nearly jokeful tone, focusing on his device.

« Yeah, like I said, you never know… » Those last words were said in a whisper, the bo-master holding back some excitement that seemed out of place.

« Hey now, stop trying to scare me… I just want to catch some good sound and call it a day », Mickey replied, feeling a bit uneasy again.

Suddendly, they heard strange noises coming from the darkness, which had nothing to do with natural sounds.

It felt… Mechanical.

Like he had been prepared for it, Donatello was already holding his bo in a fighting stance.

« Wait what ? » Mickey could just utter those words before a massive, moving pile of junk barged in and threw himself at them.

« Nice ! Now we can begin the test phase », he heard his brother shout excitedly, while he rolled out of the mech’s reach and grabbed his nunchakus, letting go of the recording device who smashed on the ground.

« What the ! Is that one of your prototypes ?! »

« My latest project, a guardian bot for the lair ! I needed to conduct some field test. I’m so glad you had this idea to go out ! »

« DUDE ! FOR SHELL’S SAKE I JUST WANTED TO GO SOUND HUNTING YOU FREAKING »

A metal fist, twice the size of its own, crashed on the wall behind him, interrupting him while he ducked.

« I’m gonna kill you Donnie ! »

« Guess you’ll have to wait for your turn, knowing our father and dear brothers. Totally worth it though ! » the genius answered excitedly, while bouncing around, avoiding the massive punches and landing some hits by himself.

« I think I’ll call him Garbot, since he is mostly made of garbage… And meant to be a guardian… And don’t worry, I’ll fix your recorder later », he added absent-mindedly.

_Oh, Donnie was so done _for, Mickey thought while fighting. Should they survive this _field test_ – and if Splinter, Leo and Raph leave something for him, Mickey would just gut the brainiac.

He would find a way to do so even with nunchakus, he sweared to himself.


	11. Duel of natures

**Summary for the Chapter:**

> (Back to the main story) Mickey goes to look for his recorder, and finds Donnie in a deep slumber, while Leo seems to be sound asleep too…

Waking up, Michelangelo felt completely refreshed. No one could tell he was missing something inside his body. He didn’t pay it too much mind anyway ; the more he would think about it, the more he would feel gloomy – and scared.

Just knowing it happened was enough for him.

He was stretching and yawning loudly, still resting lazily on his bed, when he suddendly remembered his recording device. He managed to catch some good sound before getting knocked out – it was so below the belt, by the way. How could he ever ninja his way out of such perverse, magical attack ?

Back to his recorder. Looking around, he remembered he had lost trace of his bag ; it probably was still in the laboratory – or even worse, in the sewers.

Hoping Raph had brought it along with his turtle butt, Mickey jumped out of the bed – and immediately felt a dizzy. the room was spiraling around him like a merry-go-round, and he had to grab his chair to find some support. Even sitting down on the floor, while waiting his discomfort out.

Right, hormosomething medication. Or whatever Donnie had mentioned.

Well, going to the laboratory would allow him to kill two birds with one stone after all.

Leaving his room, he noticed that everyone else’s doors – except for the genius’, of course – were closed shut. He was a little surprised, not used to be the first one to wake up. But truth be said, he had slept a lot the day before.

Going downstairs, he checked the clock in the kitchen. Indeed, it was a bit early for him, but whatever. It only meant more free time – and loads of leveling up at his favorite game.

Before eating anything, he needed to pay a visit to the family doctor, so off to the lab he went. Coming at the door, to find it surprisingly opening when he knocked. Inside, everything was quiet, the only light coming from the blue screen of Donnie’s computer. Coming closer, he saw the genius shell, the turtle asleep on his desk. Nothing really unusual, but Donatello seemed to be in a deep slumber, a rare occurrence.

He also spotted his recording device in the hand of the bo-master. He should be able to snatch it without waking up his brother. Considering the position he was in, the smartest would probably feel really sore later. And Mickey still needed to ask for the medication ; but the young DJ just couldn’t bring himself to wake the genius up. The « shell cheater » was lying in a corner of the room, next to the desk. It looked like a creepy cyclope when he was on, with his eye-like glowing light, but for now the camera was completely dark.

Approaching his brother in silence, Michelangelo managed to skillfully grab his recorder.

  


He noticed that Donnie had charged the battery up. Nice. He just had to get his headphone, and he would be able to listen to his findings while eating some breakfast.

For a second, Mickey wondered why the genius had been curious about the recording, but he didn’t dwell on it. Without a sound, he left the laboratory, closing the door behind him.

**Shortly after…**

Mickey was enjoying a cup of warm chocolate and his favorites cereals, when Raph joined him in the kitchen.

« Morniph bwo », he welcomed him, mouth filled with cereals.

« Don’t speak while you eat », Raph warned him while opening the fridge door. « Slept well ? »

  


Mickey swallowed loudly. « Just fine dude ! You will never believe what I’ve got here ! » the orange-banded turtle said excitedly, pointing at his device.

« Spill the beans, Mickey. I’m not in the mood… » Raphael replied with a grunt, sitting in front of him with a gallon of milk and a glass. The emerald turtle felt completely exhausted. He had barely slept, obsessing over a strategy to get rid of the Oni once and for all. Not to mention his shell, which felt more uncomfortable than ever.

Everything was so messed up. Well, at least there was someone who didn’t give a damn about anything, he thought while looking at his youngest brother.

« I recorded the demon ! » Mickey declared triumphantly.

Raph spit out milk through his nostrils, to the young terrapin overjoyment.

« Wait what ?! » the bulky turtle asked, trying to wipe his face with the back of his hand.

  


« Yeah, I know, it’s awesome right ? I was sure those voices weren’t only in my head ! I’m not going crazy at least », Mickey said. He was beaming with joy, and removing his headset, handed it to his brother. The red-clad cast a suspicious look at the device.

« What bro, too chicken to listen ? » Mickey was teasing him with a huge smirk, and Raph would never have admitted that he was terrified to hear his brother’s – or brothers’, considering Leo’s panic – voices screaming for help.

With another grunt, he took the headphone and put it on his earslits.

« Ok, it’s playing ! » Mickey pressed the button. At first, the sai-master did not hear anything. And then, he heard Leo scream :

_Mickey, nooo !_

« What the actual shell ! » the emerald turtle snatched the headset off his head, furious at the sea-green turtle.

« Wait bro ! I went back too far, here comes the good part ! »

« What can be considered GOOD in all this ? Did the demon fry your brain out of what ?! » Raphael was really angry at his brother. He didn’t want to hear his eldest brother using such tone, a scream of complete desperation for something he had not been able to prevent, despite all his efforts to contain the evil inside him…

« Wait ! This is what I wanted to show you, I swear ! Please bro, you have to listen to it ! »

The temperamental turtle felt his rage subside. He understood how Mickey worked, and it was so much like him, to find some way – even the strangest one – to cope with everything that had happened. That happened to HIM. He was the victim too in this story ; and it wasn’t Raphael who was missing some chunk of his liver. Breathing deeply, still staring intensively at his bonehead of a brother, he put the headphone back and waited.

The recording resumed, and then he could hear a voice.

This voice. He had heard it when he had tried to find Leo’s heartbeat. His first real encounter with the Oni, and he hoped, the last one.

Now, the sound was anything but a whisper.

_I will cut you to pieces ! I will devour your soul !_ The devil said in a deep, thunder-like voice, nearly sending vibrations in his body. It almost sounded like a powerful growl, straight from his worst nightmares.

He looked at his brother in disbelief.

« How is THAT awesome, Mickey ? »

« Dude, you don’t get it ! With Halloween right in the corner, I will make some epic mix with this ! And make some money along the way », his interlocutor answered, a huge smile splitting his face. « I can already see the downloads pouring ! »

Raphael was at a loss for words. Then, he slowly removed the headset, rolled his eyes and facepalmed a bit.

Whatever rocked his brother’s boat…

« By the way, where are Leo and Dad ? » the youngest asked, reaching for his device and placing it in a corner, focusing on what was left of his breakfeast – he felt like getting another service, by the way.

« Still napping. And Sensei woke up earlier and felt like meditating a bit », the emerald turtle answered, looking at the clock with a frown.

It was getting a bit late for Fearless. They were used to the eldest being the first one awake; everybody knew he used the earliest hours of their day for contemplation and to practice his katas, after all.

Maybe he was still exhausted from his fights with the Oni, and needed to rest more ?

Raph pondered if he should let him sleep in peace, or check on him to be sure everything was alright. He finally decided against disturbing him ; his brother needed some shut eyes.

« What about Donnie ? » he asked Mickey, who was filling his bowl again.

« Fast asleep at his desk, last time I checked. Seems like he hit the sack while listening to the recording too », he simply said.

Strange, Raph thought. How could anyone fall asleep to THIS, of all things ? Even exhaustion wouldn’t do the trick ; this thing was the stuff of nightmares.

But again, they were talking about the brainiac.

« Well, I guess it will only be the two of us for now ».

« Let’s play my game ! I feel like kicking some turtle’s ass », the sea-green turtle offered in a playful tone.

« Oh, you’re so on bro », Raph answered with a smirk.

**In the demon’s realm…**

It really was a bare land, with nothing to look at but this dark horizon, and the gray light emanating from the shadowy clouds above him ; Donatello noticed that they were continuously moving, quite chaotically.

He noticed that his senses were dimed. He felt almost feverish, like he had been poisoned. He wondered if the place itself carried some kind of airborne toxin. But he remembered it was only his spirit there – or astral projection, as Splinter named it – and that his body was resting peacefully in the lab.

For how long, though ? He was pretty sure anything happening on this plan could produce an impact on his physical incarnation. Hell, the Oni even managed to hurt Mickey outside of his realm !

In a word, the genius was in a dangerous situation, and he knew it. What would happen next ?

A muffled sound was the only thing that alerted him, before a katana's shiny blade split the air where his head was, a second ago.

« Crap ! » he hissed, performing a forward roll to get away from his aggressor. Raising his head, he saw the silvered gaze of his eldest brother on him.

« This time I’ll cut you into pieces ! » the leader yelled, plunging at him with his swords.

Donnie avoided the attack again, jumping on a higher place to look back at his brother. Or, more exactly, this simulation of the katana-master. A simulacrum of a duel , orchestrated by the Oni. If this clone was anywhere as skilled as the real Leonardo, facing him without his bo, Donnie knew he was practically done for.

For the first time ever, he started to fear for his life.

On the other side of the blades, Leonardo was driven by mad anger. He couldn’t bear this Oni’s presence anymore. The way he had tried to dominate him, control his very body and soul, and rip him from someone precious to him. He would get rid of him, he would deliver his family and himself of his hold on their life.

Slipping on the sand that was scratching his skin despite its natural thickness, Donatello couldn’t help but notice that the red glow of the possession had disappeared from the eyes of his brother’s clone.

_Wait a minute…_

Why would the Oni bother to show Leonardo as he once was, when he would be far more terrifying with his crimson eyes ? Also, despite being nearly cornered twice, Donatello understood that his brother wasn’t as incredibly fast and strong that he should have been with the help of the Oni.

And his caracteristical blue horns were missing too.

« I’ll skin you alive ! » Leonardo yelled at him, yearning for some nerd blood.

« Wait, Leo ! » Donnie shouted. He didn’t believe he would able to put any reason in the leader’s frenzied mind, but he had to try something, anything.

A sword fell between two rocks right next to him, getting stuck in place. The leader swore and tried to free it from the interstice. Donnie took this opportunity – maybe the only one he would have to save his shell – to jump away from his opponent, run at a reasonable distance, and raise his hands in a gesture of peace.

« Leo, it’s me ! Donatello ! »

« Liar ! » the leader barked, abandoning his weapon and running at him with the one left. Now, he acted like Raph, seemingly unable to hear anything. His rage was blinding him completely.

« Please, Leo ! Don’t do something you’ll regret ! »

« I won’t fall for your deceit, demon ! »

The bo-master wouldn’t be able to avoid this attack, Leo was too fast, coming at him like a cannonball.

« I yeld ! I yeld, for Heaven’s sake ! » Donnie screamed with despair, closing his eyes, trying to protect himself from the impact and avoid the blade aimed at his throat.

Time seemed suspended. Since he couldn’t feel any piece of metal entering his skin, Donnie slowly opened one eye. Behind his raised arms, he saw that the blue-banded turtle had stopped two feets away from him, his weapon still raised menacingly, a twinge of hesitation in his silver eyes. The genius barely noticed he was shaking like crazy, feeling the proximity of the leader who had wished to gut him alive a second ago. He just hoped he would be able to put some reason in him.

« Please, Leo, it’s me ! It’s Donnie !... The real one » he added, beginning to understand what probably happened prior to their encounter.

Leo had most certainly confronted some clone of him, and believed he was an emanation of the Oni. Leo probably mentioned it during dinner, but Donnie had the bright idea not to attend.

_Damn it._

  


A harsh shiver went down his spine when he thought that he couldn’t be sure it wasn’t some illusion, and that he was playing in the demon’s hands. But his only hope was that it was the real Leo facing him, and that he could appeal to his sense of justice.

« Prove it », the katana-master said in a cold voice. At least, he seemed to calm down a bit.

« …How… ? » Donnie wondered.

« Don’t try my patience », Leo replied, staring intensively at his brother, clenching his fingers on his remaining weapon.

_Oh shell oh shell oh shell._

Donnie needed to think about something fast, or he would be done for. Digging into his memory with a huge sense of emergency, he suddendly had a an epiphany.

He had to take the bet that Leo was indeed there with him, and not some clone playing with his hope to survive. If it was the case, the Oni couldn’t manipulate the leader with informations he didn’t have. Donnie’s logical mind concluded that the devil could only access Leo’s memories, and what he did know.

And Donnie’s dreams too, since he said he knew about them. But that didn’t mean the Oni had uncovered all his secrets.

« Remember this time when Stockman got away with samples of that chemical formula for an anti-mutant gas? And you wondered why he hadn’t used it afterwards ? »

Leo’s face was unreadable.

« Yes ? » he replied coldly.

« It was me… I stole it and kept it in the laboratory, under everyone’s nose. I wanted to test it to see if it really worked… »

Leo’s eyes widened.

« You did WHAT ? »

« Yeah, I know… Not my brightest move. Anyway, I’m the real deal ok ?... Your favorite evil genius.. ? »

_And this formula was a con anyway, it never worked…_ The purple-banded turtle added in his mind.

By then, Leo’s fighting stance had completely disappeared, and he lowered his katana, to Donatello’s immense relief.

He didn’t know confessing such a heavy crime would feel so good. Hell, if it was the price to pay to live another day, it was worth it.

« Brother… I… » Leo was now staring at his weapon with disbelief, unable to speak further.

He was acknowledging the fact that he nearly hurt another family member – probably ready to kill him in the process.

_Oh, for Shell sake…_ Donnie thought.

« It’s ok, Leo ! You didn’t lay a hand on me. I didn’t know I was this good at running away from you when you’re in full fighting mode, but turns out I am », the purple-banded turtle said in a southing voice, making a few steps towards his sibling.

They still had to get out of here, and the genius needed his brother to do so. Letting him fall into a catatonic state from the shock would definitely not help them.

« Listen bro, we need to find a way out… You mentioned the Oni’s realm earlier, you should have an idea how to get out, right… ? » Donnie continued, placing a reassuring hand on the leader’s shoulder and patting it, pressing his forehead to Leo’s.

Yeah, another cuddle session. Things come in threes, as the saying goes…

« Don… I’m so sorry… »

« It’s ok, it’s ok, now let’s proceed and get the hell out of here if you don’t mind ».

The leader raised his head, looking right at Donatello’s hazel eyes. Donnie gave him a encouraging smile – or at least, tried to. It had been some time since the purple-banded turtle had seen those bright, dark pearl colored eyes.

_Still, they weren’t as fascinating as their possessed, crimson edition._

They separated and Leo took a deep breath. His brother noticed that the remaining katana had disappeared from his hands.

Of course, since those weapons were generated by willpower. Donatello would never have managed such a feat. But it was best no to think about it too much.

« Well, everytime I go there, I need to fight the Oni to break free… » Leo said, frowing and looking around for a sign of the demon.

« Then, we just need to find him, right ? He must not be too far… »

Donnie could not finish his sentence. A deep rumbling echoed in the empty space around them, whirling like a stormy, hot wind.

_I’m here and everywhere_, the now familiar voice hammered.

It felt like a powerful pounding into their brains, and the two turtles hissed in pain. Leo, more used to it, was the first to recover.

« Come here and face me, you coward ! I know you’re afraid of me now ; come fight me ! » he yelled at the sky.

All of the sudden, Donnie got projected in the distance, like if he was on a fast moving train rushing into a large, dark tunnel.

_You used trickeries to save your life…_ The deep voice ringed into his ears.

« Trickeries ? I told the naked truth », Donnie answered, looking around. He had arrived into a completely empty space, surrounded by pure darkness.

Suddendly, he spotted two red glowing eyes, far bigger than the ones of the leader.

He was alone with the demon, now.

In his room, Leo woke up all of a sudden, sitting on his bed, his heart beating like crazy. Panting, he tried to calm down. Then it came to him.

The dream. The fight.

_Donatello._

Jumping out of his bed, he lost balance and hit his closed door loudly.

« Leo ? » two voices said in unisson, coming from downstairs.

Trying to shake the dizziness out of his body, the leader rushed to the stairs and nearly stumbled again when he reached the ground floor. Immediately getting up, he saw Raphael scurry to help him.

« Easy, Fearless ! What happened ? What’s the emergency ? »

« Dude, you look like you’ve seen a ghost ! » Mickey said, while sitting on the sofa and looking at him. In the background, a game had been paused.

« Very poor choice of words, Mickey », Raph scolded him.

« Sorry… » Mickey said, biting his lower lip.

« Where is Donnie ?! » Leo asked frenetically.

« Still sleeping in the lab I believe », Mickey answered while scratching his nose. « Which is kinda weird by the way, since it’s nearly noon. What’s up with the long nap ? »

« We need to wake him up ! Right NOW ! » The leader said, pushing Raph out of the way and running to the lab’s door.

Fortunately, it was opened. He barged in and spotted the collapsed figure of his brother on his computer’s desk.

« Shell, Donnie! Wake up! » he grabbed him by the shoulders and started to shake him violently.

Raphael and Mickey, seeing how worked up the eldest was, had followed him into the genius’s lair and helplessly looked at him assaulting their brother – again. Even Splinter showed up a few seconds later.

« My sons, what happened ? » he asked, trying to get a grasp of the situation. The red-clad turtle wondered if he should, once again, separate his two brothers. However, Donnie saved him from the hassle, waking up in panic.

« What ! What the heck ?! Arrgh ! » Seeing Leo so close to him again, remembrances of their recent encounter clouded his mind and he jumped out of his reach, knocking a few beakers down – which shattered on the hard floor, projecting glass everywhere.

« Donatello ! » The old rat caught the turtle before he would fall on the nearby echograph.

In the midst of all the turmoil, Raph still had a second to wonder how their father always managed to be so incredibly fast.

« Did the Oni attack him ? » the wise rat asked, lifting his barely awake son up and steadying him. Donatello was looking at the assembly with wide eyes, still recovering from his violent awakening.

« Yes, he attacked both of us in our dreams », Leo answered. Then he added : « He made me believe Donnie was a clone, and fight him ».

Their sensei could not hide the pure terror that passed on his face when he considered the implications. He knew his other sons weren’t good with the astral plane. They didn’t have this affinity, and astral strengh, Leonardo had acquiered with dedicated training. It could have gone wrong, really wrong.

He turned around the bo-master and, taking his face in his hand, lifted his head up to look into his eyes.

The turtle looked completely at a loss, but his spiritual energy remained intact.

« I didn’t touch him », Leo continued. « He managed to prove to me that he was my real brother… »

« How so ? » the old rat enquiered, still looking at his other son while stroking the olive green cheek. Donatello was coming to his senses and, feeling the furry hand on his face, he looked at his father awkwardly. Repressing a sigh, his father let go and looked at his eldest instead.

« He told me something the devil couldn’t possibly know… » Leo answered, casting an accusatory glance at his genius brother, now that he knew he was safe. They would have to address this _something_ later on, but for now, he had to make sure the bo-master was ok.

« What happened afterwards ? Did you get separated ? » Splinter asked, stroking his beard, in deep thoughts.

« I saw Donnie being sucked in some sort of black hole. The Oni often uses those dimensional anomalies to change planes when we fight. He also did it last time to make me relive the events at the research center… »

Hearing those words, Raphael gulped. He hated to be reminded of this dreadful night.

« Then, Donatello, tell us if you remember anything after being separated from Leonardo », their father asked the genius.

« I… Can’t recall much. Indeed, I saw myself being projected far away from Leo… In a dark tunnel… And then the Oni’s eyes on me… But I don’t remember anything else, Sensei », he answered in a slightly shaken voice.

« Hmmm », the old rat muttered.

« Maybe you should, you know… Echograph yourself or something », Mickey added, pointing at the device.

They all fell silent for a moment.

« Good idea », Master Splinter finally said.

Donnie didn’t reply, and just nodded.

**A while later…**

After recovering from his emotions – and the harsh « Leonalarm clock », as Mickey had nicknamed it – the genius conducted a serie of medical tests on himself, and everyone felt relieved when he announced everything was alright. He wasn’t hurt anywhere and his internal organs were just fine, retaining their original mass.

His family even went into another round of forceful hugs – according to Donatello – to show their happiness. Finally, after the family doctor used the remainder of the day to fix some hormonal medication for Mickey, their father decreeded that they would all have pizza.

During dinner, Leo told her how the Oni seemed to avoid engaging him directly now, like if he was really weakened and somehow, afraid.

All this time, Donnie barely said a thing, but no one paid it any mind since they were thrilled by the prospect of Leonardo freeing himself from the possession. So he just sat there, picking at his pizza slice without eating much, and watching his brothers enjoy their dinner and joke around, in their first relaxed and serene evening after so many weeks of moping.

_Oh, Leo would be all right. Donnie had no doubt about it._

_Because now he knew so much more about all this. But he wouldn’t tell anyone yet._

_He would just have to keep lying, and everything would be fine._

* * *

I just published my own website with my fanart and other works. You can visit it [here](https://chemistryofadream.wixsite.com/mysite) :-)

**Notes for the Chapter:**

> I'm starting to receive art commissions and I'm getting a bit busier everyday, so I'll try to update the story as fast as I can.


	12. Back to the night

**Summary for the Chapter:**

> Now that the turtles have found some respite, they decide to return on patrol topside. And Mickey does not want to be left behind...

Mickey felt feverish again. Nothing alarming yet, but still, he was weaker.

Donnie had fixed him some liquid solution to take with his morning fruit juice – and it tasted so bitter that it completely ruined the sweetness. However, the young terrapin was told he could not afford to make things difficult.

« I synthetized some hormones with samples I took from myself », the genius had said. « I couldn’t risk using Leo’s or Raph’s blood, for I’m not sure about the Oni’s impact on our leader’s metabolism – and I’m affirmative Raph’s organs are too mutated for this », the genius added while handing the seagreen turtle a bottle labelled with his name. Mickey couldn’t repress a shiver, hearing someone talk about their brothers’ conditions with such nonchalance. But again, it was Donatello.

« Take a sip everyday. It’s necessary to maintain your energy homeostasis », the genius had added. Mickey had casted a blank gaze at him.

« More English, less scientific nerdy slang please ? »

The family doctor had sighted, pinching his foreheads while closing his eyes.

« We need to keep your energy depletion under control… Look », he added when he saw his brother’s expression, « it’s like when you fight in your videogame : the more you use special technics and magic, the more your stamina and mana will decrease ».

« So now, I have like a life bar above my head? »

« Yes, you can put it that way », Donnie replied.

« Ok… I can live with that ».

« But there is no revive or respawn in THIS game Mickey, so be careful and take your meds. »

« … Cold », the seagreen turtle had said between his teeth.

After being reminded to come to the lab once he finished the bottle, Mickey had been sent on his way.

It had already been a few days, and nothing noticable happened afterwards. They were all grateful for it ; training and normal life resumed, with a nice addition : Mickey wasn’t required to train as hard as before, Leo’s fearing for his health and willing to stay on the safe side. It allowed for some more music sessions. Right now, the DJ was busy working on his next composition, « Devil under my shell ». The Oni’s voice worked smoothly with his mix. He just had to record some good thunder rumble, and it would be perfect.

However, having more time to himself also meant the orange-banded turtle was in for some cruel reality check.

« that’s so UNFAIR! What do you mean, I can’t come on patrol with you guys ?! » He shouted at Leo, who was equiping his katanas and frowning at him.

« You know why, Mickey. You’re feeling the side effect of the hormonal supplementation. Don told me you had some light fever this morning », he said in a calm tone, sheathing his weapons.

« That’s the operative word, Leo ! LIGHT fever, like in, nothing serious. Come on, you can’t seriously force me to stay locked up here ! I need to bath in the beauty of the night, the sounds of the city, to sustain my creativity ! And also », he added in a dramatic tone, « I want to kick some ass too ! »

« I’m not sure you are in a state to kick ass, the way you are right now. You haven’t even trained properly this last week. »

« Well, that was your decision, not mine » the youngest answered, crossing his arms. Yes, it was greateful for the extra napping and such, but not to THIS price. Leo looked at him. There was no sense of self-importance in his expression, no leader’s prerogative; just those gentle, worried eyes, making Mickey feel all warm and fuzzy inside. Despite the Oni, his eldest mother hen’s nature could still shine through the red glow.

However, the nunchaku-master was angry and not ready to let go.

« That’s not fair, period ! Even more now that it’s raining ! I was hoping for some thunder sfx », he pouted, avoiding Leo’s concerned gaze.

« Come on drama queen, you can find those for a few bucks on the Internet! » Raph intervened. He was putting his belt on, trying to make it slide on his deformed shell.

« But it’s not the same ! » Mickey was close to throwing a tantrum like a kid, now. « You can call me names all you want, I’m not going to let go ! Leaving me here alone is unjustified, I’m not a dying turtle and I can handle myself just fine ! »

Leo bit his lower lips, feeling the guiltiness sink in him. It was his fault Mickey was on house arrest, and for who knows how long. He cast a glance at Donatello, who was coming back from the dojo, his telescopic metal stick in one hand.

The leader didn’t like this weapon one bit, and refused to call it a bo. When the genius had first presented this new _project_ to his family, they were more than doubtful with the « upgrade » nature of it. And they were all very concerned, and a bit angry, when they saw the « special feature » : an electrical conduction system, which would allow to induce short-circuits while protecting the wielder – thanks to an insulating sheath in the middle.

Or so the purple-banded turtle said. The eldest would not be fooled, and was adamant on the fact that Donnie would not use the highest voltage on living foes.

At least, the genius had agreed, but it really looked like it was stealing all the fun.

« As I already said, I believe Mickey can join us », said-turtle said in a nonchalant tone. « We may go slower and see how he adjusts to his new condition ». While saying so, Donnie was tapping the side of his head – probably his so-called _neural implant_ – while seemingly making some adjustments with his shell robot.

HAL 5’s camera lit up and, stretching the improbable metal neck that supported his video unit, he looked at the assembly, narrowing his light to an orange circle when he focused on Leo. It was like he was really _watching _them, recording everything to feed his deep learning. He also moved his robotic hand a few time, spreading and tightening his clamps like if he was warming them.

Creepy as shell.

« See ? SEE ?! If the Doc himself says I can go, then I can go ! » Mickey wasn’t sure if he hated or loved his smartest brother right now ; after all, the genius gave him as much reasons to like him than the opposite. So for the time being, he would settle for feeling _neutral _towards him.

After all, he already had some hidden, limited health bar above his head, he could have a game character’s alignement too, right ? Wait, so it meant he should have to choose another one for Leo and Raph. Could « pissed » work here ? Because he sure was !

Raphael cast an hesitant look at the genius before asking : « You sure Donnie ? »

« I’m positive. He didn’t have any concerning sequel, none that I observed anyway, so I say we let him join. Otherwise, his mental stability may be impacted on the long term ».

« Yeah, that’s right ! I’m mentally unstable… At least if I stay grounded here like a naughty kid ! »

« You’re not grounded Mickey… » Leo sighted, facepalming.

« Listen Leo, let’s try for now and see how it goes. I’ll stay behind the bonehead just in case », Raph added.

Leo raised his head, a tired smile on his face.

« Ok. Thank you Raph… »

« Don’t mention it. So, are we going or what ? » the red-clad turtle barked, reddening a bit and walking to the entrance of the lair. He then stopped and waited for them all to pass him, before following Mickey.

« You better tell me if anything’s wrong », the temperamental turtle said to his brother half-way between menacing and caring.

« Of course bro! I’ll be sure to puke on you if needed », the katana-master answered jokingly before avoiding a half-hearted punch with a laugh.

Ahead in the tunnel, Leonardo and Donatello were walking in silence, side by side. Without looking at his brother, the leader asked in a low voice :

« Are we sure about this, Donnie ? Isn’t this a little bit… Too soon, I mean, for him to jump from building to building? I’m not even talking about Purple dragons or, even worse, the Foot clan… »

« As I said, we will be better off taking him along. Just imagine how it would ruin his mood if we forced him to stay put everytimes we go on patrol ».

Suddendly, the genius stopped, to the leader’s surprise.

« There is something you don’t seem to understand, Leo ». He said slowly, looking at him with a serious expression. « Michelangelo’s condition is NOT temporary. He may be on hormonal support for the rest of his life. It is primordial that he learns to live with it and function properly as a ninja », he added, unflinching.

Saying those words, in such a detached tone, to the very person responsible for their brother’s sad state hit Leo like a hard blow. He paled, to Donnie’s indifference who simply resumed his walk, passing him without a glance and disappearing into the tunnel in front of them.

« Dude, what are you doing, daydreaming in the sewers ? Keep going or we'll leave you behind ! » he heard behind him, Mickey joining him with a cheerful attitude, Raphael on his heels.

« Everything’s alright Fearless ? » The emerald turtle asked when he saw the leader’s expression.

« Yeah… Let’s go », Leo said, hurrying to catch up with Donatello.

_Sometimes, dealing with the genius really felt like chatting with the Oni himself. No, it was even worse ; the blue-banded turtle didn’t have any attachment to the demon – of course. This thing wasn’t part of his family._

_But Donnie was. The katana-wielder felt like he should protect and lead him like his other brothers, but sometimes, it just felt too hard. _

_Too hard to care for him. Too hard to even love him._

_But Leo had to be strong and not resent his brother. They needed him, and he was en essential part of their harmony. Whithout him, something would be amiss. _

_And he still had to address this revelation Donnie had made to him about the anti-mutant weapon. _

_However, the leader had yet to find the courage to do so. _

« So, I’m on watch duty or you are ? Because, if you keep lagging behind, I’ll let you deal with the knucklehead », he heard Raph say to him.

Indeed, they had reached the surface but he was still stopping from time to time, willing to put some distance between him and Donnie. That’s why he found himself tailing Raph, instead of leading the way like he should have.

« Sorry… » Leo muttered. He raised his head to look at the sky. There was barely any cloud at the horizon, to his relief and Mickey’s utter disappointment. The forest-green turtle didn’t like to patrol under a heavy rain, and New York was known for his showers-like weather. Especially in autumn. However, there was a chill in the air that he didn’t like.

« You look like you’re completely out of it. Still worried for the blockhead ? » Raph asked in a concerned voice.

« I guess I am, yes… It’s a bit cold tonight », Leo replied.

« Yeah, not gonna get better anytime soon, you know ».

_Oh, he knew just right. _

_Same for Mickey’s condition._

In front of them, said turtle was taunting Donnie.

« Hey Don, do you think this salad gripper could lift my weight ? » the youngest said, pointing at the robotic arm behind the genius’ shell.

« If you are talking about HAL 5, I would ask you to stop deriding him. He understands what you say, you know », Donnie said, approaching his youngest with a smirk. « And he never forgets anything, especially since he uploads all his raw data on the deep web… »

« I sure hope this thing is not sharing our mugs on social media », Raph growled, looking suspiciously at the red-glowing camera which – of course – turned his direction immediately and stared at him.

« Of course not. Do you think I’m stupid or what? » Donnie answered, in a tone that tried to express how much he was astonished by his brother’s very poor ability to think properly. « Raw data does not work this way, and his cloud capacity is completely restricted. No one but me can access it. And I was obviously joking about the deep web », he added.

« Yeah, obviously… » Raphael repeated, clenching his teeth.

« Uh… Guys ? » they heard Leo call for them, and came closer. He was standing at the edge of the rooftop, looking at something below. They followed his eyes and saw five shadows fidgeting in front of a closed storefront. One of them was in a squat position, holding something that looked a lot like a home-made explosive device.

« Purple Dragons. They gonna bust the door », Mickey whispered.

« Thanks, captain Obvious », Raph answered.

« Hey, I’m trying to be useful ! » the youngest pouted.

« Stop, you two », Leo said in his leader’s tone.

Silence.

« Ok, it’s only five of them, I can handle them alone », Raph said, preparing to jump in the alley.

« Wait, Raph ! They have C4. I don’t want you to act recklessly like you always do and get your shell blown ».

« Come on Fearless, do you think I’m stupid ?! »

« Not so nice when you’re on the receiving end, is it now ? », Donnie smirked.

« Shut it brainiac ! »

« Guys, will you calm down or what ? What happened to our training for control and stealth ? Did you forget we’re ninjas ?! » Leo felt like running out of patience himself, but tried not to show it.

Silence again.

« Ok, I’ll go with Raphael. You two stay here », the leader said to Donnie and Mickey, with a tone that didn’t invite to discussion.

« Fine… » Mickey said. He wasn’t happy with the way they were leaving him behind, but at least he was allowed to tag along, and it would be enough for tonight.

Donatello didn’t say anything and just went to sit down on the ledge, turning his back to him and assuming watch duty while the two fighters jumped down without a sound.

Leo gestured Raph to take the thugs on the right, while he would deal with the goon with the bomb and its acolyte on the left. Nodding, the sai-master jumped and dealt a quick, silent blow to the man closer to him. He caught him before he could fall and dragged him out of the way, without alerting the others. Meanwhile, Leo was approaching his own group using the cover of shadows.

One of the thugs was cracking a smoke when he felt a presence just behind him. He couldn’t even scream before the sai handle made contact with his chin, knocking him out. The third one jumped backward to get his knife out – only to take a massive foot kick into the stomac and fall on his knees, grabbing his belly and panting. Raph silenced him with one well-placed uppercut.

« They didn’t put much of a fight », Raph grunted. « Boring ! » he turned around to see Leo letting the last opponent fall on the ground, unconscious.

« Sometimes, it’s better this way », the leader simply said, while looking at the explosive device which had been left on the ground. It wasn’t armed yet.

« Let’s call the cop and call it a night », he said while getting up.

« What ? Already ? Come on Leo, let us try to find some Foot ninjas at least ! »

« Raphael, don’t you think that’s enough ? Think about Mickey ! »

« HE IS FINE ! And he wouldn’t be on the front lines, WE would ! Along with Donnie and his freaking shell sheater ! » Raph barked at him.

« Yeah, I know, my robot is one sick badass », they heard from behind. The genius was standing a few feet away, looking at the scene.

« The bomb hasn’t been activated. Let’s call 911, but we’re not going home yet ! » Raph said, pointing at the leader.

« Donnie, did you leave Mickey alone ? » Leo asked in a concerned voice.

« Why, yes ? I don’t think he needs constant babysitting », the genius answered.

« What if something goes wrong ? You two should make sure he’s never left behind! » Leo yelled at him.

Raphael looked at the leader with wide eyes.

« Jeez, Fearless… Ok, chapron’s mode back, no need to get your panties in a bunch ! » the emerald turtle said, walking to the building to climb it.

However, Mickey was already joining the group.

« What’s with the long faces, dudes ? » He asked.

« Nothing. Let’s move on », Leo answered.

« Wait », Donnie said.

« What ? » three turtles asked simultaneously, some a bit irritated.

« HAL 5 intercepted an alarm activating on the East side ».

He waited, probably gathering more informations, and then looked at them with dismay.

« It’s… The research center ».


	13. Foot in the door

**Summary for the Chapter:**

> Will Raphael be able to go back to the place he loathes the most on Earth ? Despite underlying fears, the four turtles have to make sure that no one is trying to misuse those research, and they may even need additional help…
> 
> Casey’s entering the story on this chapter.

Raphael felt like someone had punched the breath out of him. Panting, his vision blurring, he nearly fell against the nearest wall and grabbed its edge to find some support.

_The research center._

_The tanks._

_The green water. _

No way in hell he would go back there. But he didn’t have much of a choice ; if the foot was to get its hand on the mecanic mutating process, they would not even need the mutagen anymore. It was even more handy for them, since they could probably retain human forms and still gain various perks. Donatello had once said that some animals were known for their virtual ability to regenerate, like the turritopsis dohrnii, known as the « immortal jellyfish » ; or the chitons and their magnetite teeth…

Raph had not deemed useful to retain all those scientific classifications of the animal world ; he only knew him and his brothers would be in deep trouble, if their enemis were to use some freaky « natural » superpowers against them.

Which reminded him what their resident genius often said to him : « you could make the best of your current condition, you’re wasting a great opportunity ».

Yeah, how lucky the red-clad turtle had felt until now…

« Are you alright, Raph ? » This time, it was Leo’s turn to feel concern for him. Truth be said, his bulky brother was pale as one with emerald scales can be.

« Dude, you’re nearly my color now », Mickey added, coming to his right side and touching his arm in a soothing gesture.

The sai master felt completely miserable.

« When you feel better », they heard behind them, « I believe we should get moving. It won’t take them much time to subdue the security there ».

_Well, dear Donnie just knew first hand what he was talking about, right ? _Mickey stared at their brother with a rather unamicable expression, while Raphael took a deep breath.

« He’s right. Don’t worry ‘bout me and just go, I’ll tag along ».

« No. You’re in no state to fight as you are right now », Leo answered with a frown. « I’m serious, Raph ; If you come with us you’ll put yourself in danger, and we may not be able to cover for you ».

« What the hell ?! I’m just a bit shaken ‘k ? Not everyone has to be fearless and awesome all the time like you are ! »

The three remaining brothers – including the turtle involved – looked at each others in surprise. It had been so long since Raphael had sought confrontation with the eldest, it felt nearly… Nice. Refreshing. Like things were, indeed, getting better.

« I have an idea ! Let’s call Casey for backup ! » Mickey suddendly said. « With another hothead onboard, Raph will feel better – and we can use the additionnal fists », he added, proud of his tactical contribution to their fighting strategy.

Leo kept silent for a moment, before saying : « You’re right. I believe we’ll need help on this one. Raph, call him and tell him to join us there. We’re going first to assess the situation », he concluded before jumping to the nearby rooftop, motionining his two other brothers to follow him. While taking his Tphone out of his utility belt, Raph could swear he saw the glimpse of a delighted smirk on the brainiac's face while he ran away ; but the emerald turtle couldn’t stare for too long, since Donnie’s creepy robot turned around to point his cyclop eye at him.

_This wrench was getting on his nerves._

He dialed his friend’s number and waited, before hearing someone pick up the phone and a familiar voice say :

« Yo Raph, what’s up ? Been a long time ! » Casey said cheerfully.

« I’ve got some action for you, if you’re up to it », the ninja answered, trying his best to sound confident.

« What a way to ask me out, dude ! What’s on the menu ? Purple dragons ? Street gangs ? Bebop ? »

« Even better. The Foot clan. We need some backup for this one », Raph simply said.

« Sounds serious and dangerous », Casey said, delighted. « Count me in ! »

« Perfect. I’ll give you the address. Don’t be late. »

After indicating the location, both hanged up and Raph started to run to join his brothers. He had the time to calm down a bit during the call, but his mind was still a mess.

_You’re wasting a great opportunity._

« Shut up brainiac », he hissed between his teeth. He didn’t need his evil brother's voice to haunt his thoughts.

What did Donnie even know ? What did he understand about them all, what they had gone through ? He would not even be able to keep the Oni at bay, and nearly got his smartass beaten by Leo himself.

Still, Raph was glad nothing serious happened back there. It was one thing to resent his brother, but it didn't mean the emerald turtle actually wish him harm.

He quickly closed the space between him and his brothers – Raphael was a fast runner, especially for short distances. However, Leo and Mickey easily outdid him in the long run.

He stopped at the edge of a bridge, looking ahead. Thanks to the full moon finally appearing behind the clouds, he recognized the shadows of the other ninjas, kneeling on a rooftop. He recognized his surroundings immediately.

The research center was just behind this office block. To reach it, he had to jump back into the street and run for the cover of the shadows.

_Or…_

A fleeting thought about his wings got immediately dismissed.

He didn’t know how to use them, and would not try to learn.

_Especially not TODAY._

Sighting, he jumped below the bridge and resumed his race.

Leo was observing the scene in silence, Donatello recording everything with HAL 5 and probably pondering all parameters at the neural level, while Mickey just kneeled next to them.

« Phew, there’s a lot of them down there », the youngest whispered.

And he was right. The leader had at least counted a dozen of them just saying outside, probably on watch duty – looking out for any sign of THEM, the katana-master suspected. He could probably count on the same amount of Foot ninjas inside the building.

« It looks like they killed the guards », Donnie observed with an evened tone.

Leonardo looked at a patch of shadow near the building. He saw bodies being dragged in a corner, two of them. They weren’t moving.

« Knocked out maybe… ? » Mickey said hesitantly.

« They’re going cold, according to HAL 5. Human bodies take nearly one hour to lose one celsius degree… However, it’s quite chilling tonight and my robot is highly sensitive in measuring body temperature. So yes, they’re dead » Donnie added.

This heartless and methodical analysis was more chilling than the weather, both Leo and Mickey thought.

So the Foot clan was here to kill, which wasn’t really a surprise. Schredder must have been adamant that he wanted whatever this research center had to offer. Leo wouldn’t be surprised if the team involved got already kidnapped, or even worse if they refused to collaborate. The criminal organization had his own « scientists » ready to be purchased and conduct whatever research their boss ordered. They didn’t need external unwilling « partners ».

« Ok, I believe the three of us can take care of the sentinels », the leader said while drawing his weapons.

« What ? You don’t want to wait for Raph ? »

« He wants to make the job easier for him », Donnie simply said while ajusting something on his shell sheater’s robotic arm, still touching his head and controling it with his mind.

Leo didn’t comment on this.

« Follow my lead, ok ? One, two... Three ! » the ninjas jumped from their position and managed to land strategically – meaning, each one on top of a Foot ninja. Donatello had equiped his telescopic bo and, conduction activated on it, slammed it on the head of the nearby opponent while he placed a quick Ura Shuto on the one’s neck he was sitting on, jumping as his victim fell on the ground, uncounscious.

Mickey had placed two rotating kicks in the melee while handstanding on his ennemi’s shoulders, making him lose balance and fall – a well-place nunchaku quickly putting him to sleep.

As for Leonardo, he had landed, katana’s handle first, on the head of the first ninja, striking two others who had come running to corner him with foot-reverse kakushi geri, and a classic side kick.

Swift and clean. With the benefit of the surprise, they had gotten rid of seven ninjas and rushed to engage the remaining foes. Donatello got two of them at the same time, and was about to order HAL 5 to grab one of them when they heard two animalistic roars coming from the nearby street, and a characteristic battle cry.

« Goongala! »

« Yep, Casey has joined the chat », Mickey said jockingly, while avoiding a blade.

A hockey stick hit his opponent in the back of the head, effectively getting the turtle rid of him.

In the same time, a thrown sai planted itself into Donnie's adversary’s arm, distracting him while the genius dealt him the final blow.

« Two down, three more to go », Mickey said.

« Come one dude, let us have what’s left », Casey answered, his voice muffled by his hockey mask.

« I believe Raph already got them », the seagreen turtle said, looking at his brother who was in the process of disarming and wrestling one of them, another one already lying on the ground at his feet.

The last one was about to run inside the building to alert the others. Raph was aboutt to aim at him with his other weapon, when they heard the sound of a lazer shooting.

The ninja fell face first, shot in the leg.

« Donatello ! » the leader shouted, catching up with the ninja and kicking him unconscious. Two turtles and one human looked at the genius with disbelief.

« What did I say about that cursed gun of yours ? » Leo was red with anger, marching to his brother with a threatening stance.

Said turtle backed down on instinct. 

« He was about to give the alarm ! » the genius answered, raising his voice too.

« Well, I believe they already heard the commotion », Casey said, looking at the building’s door.

« Not necessarily », the brainiac continued. « I’ve already been there, the walls are thick and reinforced to prevent a possible leak... Or an intrusion », he managed to say before Leo grabbed him by his shell, HAL 5 camera immediately closing in the leader’s face, nearly touching it.

« Move that damn cyclop out of my way ! I told you to never use this weapon on a living opponent, for shell sake ! »

« Jeez, calm down Leo ! I shot him in the leg, OK ? He will be fine, he won’t even bleed since the wound is already cauterized. I can’t possibly understand why you have a problem with me using my ray gun, when it’s perfectly normal for Raph to impale people with his sais ! »

« It’s a gun ! The same weapon used by street gangs and what-not ! where is your honor as a ninja ? How can you even use this ? You’ve been trained to fight fair, not play the trigger-happy goon ! »

Leo was lecturing the genius for good now. But they needed to move on, and fast, so Raph stepped in and said :

« You can have his ass later bro. For now, I believe we should get going. We don’t know how many of them are inside the building. Even the Shredder could be there for what we know ».

It was incredible, how they hadn’t forseen this. After what happened to Raphael, it was only a matter of time before the Foot clan would catch wind of the kind of research they were conducting here. But the Hamato clan had been too busy with their own problems to pay attention to it.

Especially Donatello, whose job was to monitor their whereabouts. However, he didn’t feel too guilty about it, as they climbed the stairs and walked along the corridors in silence, all cameras around them busted and out of service. All lights were also out, but they knew how to look since only one floor had its door lock picked.

_It was always « Donnie, help me here, help him out, do this, prepare that… » _

_He couldn’t be prepared for anything, all the time. And currently, it was like everyone expected HIM to provide a solution for everything. Him who nearly got killed not so long ago, after all – even if it was only in a dream. _

_When would this predicament stop ? _

Also, the genius was growing REALLY tired of being shaken like a rag doll by an emotional leader. On his back, HAL 5 was moving relentlessly, opening and closing his clamp, filming all around – and especially, following Leo closely as he moved in the shadows.

Donnie had to be careful, or the robot would register instructions from his reptilian brain instead of the rational neocortex.

_Which meant he would become dangerous._

Behind him, Raph was doing his best to keep his breath under control, while Casey and Mickey followed closely.

« So, hu… » Casey started whispering to the turtle at his side, « Why am I here again ? It does not look like you guys imperatively need my help… »

« Well, remember what happened with Raph’s shell ? » Mickey said in the lowest voice he could manage.

« Yeah, what with it ? » the man answered, casting an involuntary look at it.

« It happened here… » Mickey simply said.

« Ah shit… Now I get it » , Casey said while watching his friend battle some well-hidden panic. He clearly wasn’t comfortable at all being there, but the human had to salute the self-control the red-clad turtle was showing.

« So yeah, we thought that calling you as backup would be wise… You know, like some emotional support between hotheads ? »

« What, so I’m like an assistance animal ? That’s it ?! »

« Exactly dude ! » Mickey was struggling, not to burst out lauging. He definitely should fix some ID card or badge for their human friend next time they meet, to increase the fun.

Suddendly, the little team stopped when their leader paused their progression abruptly. He had caught a voice he hoped he would not hear under those circumstances.

« Karai », he whispered.

Leonardo stood completely still, to make sure he had heard well. But there was no mistake, as the voice echoed again behind a semi-closed door, at the end of the corridor.

The kunoichi was here.

**Notes for the Chapter:**

> This little picture is one of my first traditional drawings. I like the fact that I managed to draw HAL 5 crowding the two brothers during their altercation :-)


	14. Story illustrations: new art

**Summary for the Chapter:**

> Here are some other drawings I made while writing the story. Mickey and Raph have the spotlight!
> 
> First one: "DJ Glasshell", Mickey composing his next piece
> 
> Second one: "One of those mornings", Raph waking up after a long night (See chapter 7: Twisted feelings)

You can also see my art on [Deviantart](https://www.deviantart.com/chemistryofadream) or my new [website](https://chemistryofadream.wixsite.com/mysite)!

**Notes for the Chapter:**

> I received a few requests to actually draw the comic of the story. Do you think it would be a good idea? Let me hear your opinion! :-)


	15. Unceremonial onslaught

**Summary for the Chapter:**

> Karai being there does not help our favorite leader, while Raph still struggles with his dreadful memories. Will Donatello be able to fight like a true ninja ? Will the team be able to prevent the Foot clan from stealing those dangerous scientific data ?

_Karai_, Donnie thought.

How would their leader react now that his biggest weakness appeared ? They should have known, once again, that Shredder would not want to expose himself for this kind of « side operations » ; it wasn’t a cause noble enough for his master ninja’s skills, nor a real challenge. Unless four ninja turtles and a human hockey player decided to show up, that is…

Waiting for Leo to decide on their next move, Donatello looked back at the little team immobilized in the darkness ; Raphael still contemplating the ground, probably scared to acknowledge his surroundings and the « familiarity » of all this. Their human friend scratching his nose, probably wondering why the presence of the kunoichi changed anything, and Mickey, who raised his head and crossed his brother’s gaze.

Last time they were here, the youngest had beaten the shell out of him – well, at least, tried to. Donnie hadn’t equipped his robot back then ; having disabled all electronical and mechanized security around the perimeter prior to his « visit », he thought his hacking skills and conductive bo would be enough precautions.

If he had brought HAL 5 along, the exosqueleton would have probably proceeded to rip Michelangelo’s head off, when said turtle threw the first punch in his face. Right now, the youngest was probably also remembering the events of that peculiar night. And his eyes were anything but friendly.

Oh, he still resented the genius alright. It certainly was an unproductive way of thinking, when someone got so driven by his emotions, that he couldn’t move on – at least not completely.

Kinda like their leader, who locked concerned eyes on the door.

Those last months, Leonardo had done everything he could to avoid crossing Karai and her goons. He wasn’t afraid to fight, and knew how to keep his surnatural strengh under control ; but he didn’t want her to _see _him. The way he looked right now, with his crimson glowing eyes and his cristal-blue horns. What would the kunoichi think of him ? Her, the Chunin of the Foot clan, learning that her opponent resorted to an Oni because he was unable to help his own brother, and got betrayed and possessed ?

Eveything happening to him recently screamed of his weakness and his inability to protect his own family.

_Raphael got mutated against his will, the worst way possible._

_Michelangelo got badly hurt by the demon._

_And him, Leonardo, the leader of the clan Hamatao after their sensei, got possessed and couldn’t even free himself._

Against all logic, the katana-master believed that somehow, someone as strong-willed as Karai would have been able to resist the demon’s hold.

So here he was, nearly panicking, not willing to show his current appearance to the one person he didn’t want to disappoint. Yes, she was an enemy, but she had shown there was some light, and hope for redemption, in her heart. Master Splinter would be so pleased, if he could have his daughter Miwa back.

But would she ever consider coming to their side, if she saw how weak Leo really was deep inside ?

The leader had to make a quick decision. He couldn’t afford to let the Foot clan get their hand on those procedures either ; Raphael more than attested to their dangerous nature.

Feeling his heart tighten, he turned around and, looking at his little team of fighters, gestured them to move forward and prepare themselves for the impending confrontation.

_She would see him, and there was nothing he could do about it._

A burning sensation at the back of his head told him that his smartest brother was staring at him.

Indeed, Donatello was somehow impressed : their leader's sense of duty really overwhelmed everything else, including hormonal attraction towards a potential mate – one he was really into, furthermore.

As for Raphael, he was walking in silence. He would never admit it, but he was admiring Leo right now, for he knew the choice he made must have been a tough one. Everyone knew how much Leo « liked » Karai and hoped to convince her to join them. It was farfetched to talk about romance in their case : they were both leaders of a ninja clan, living their life like there was no tomorrow. But it didn’t mean they were unable to feel things. And those feelings were especially strong on his brother’s side.

That being said, the red-clad turtle didn’t like the kunoichi at all, and was pretty sure she would betray them one way or another – even if she decided to fight on their side. Her faith and devotion to her adoptive father was too strong, and she only dreamt of making him proud. They couldn’t win against such one-track of a mind, was what Raph believed.

But he didn’t voice his concerns too loud, at least not so much anymore. Leo’s heart was heavy enough right now, not to add some additional emotional pain.

Sighting silently, he reached for his sais. The team came to a stop near the door, and Leo gestured Raph to take the front line. Donatello would immediately follow, Mickey and Casey closing their attack formation.

At least, it wasn’t the same place as where the green-goo tanks were. Those were located at least ten floors under ; in the underground levels. For now they were in the offices area, on the eighth floor, and Karai was probably looking for files and schematics of the experimentations.

The sai-master just hoped they would not have to go downstairs afterwards.

Leo took a quick glance inside the room, and indicated there was at least twenty people in there – probably a wide open space. Karai was still giving orders around, and they could hear the faint sound of people rummaging through documents and typing on keyboards – with ninja skills.

With an ever greater stealth, the forest-green turtle moved around the slightly open door and, barely opening it further, kicked the closest opponent in the back, projecting him against another one. They couldn’t recover from the surprise before he jumped inside the room, Raph on his heels, weapons at hand. Karai immediately turned around to see the intruders, and recognizing the turtle, she unsheathed her own katana – only to be able to stop Leo’s direct attack. Blades clashed against each other, and the two of them looked into each other’s eyes – Karai nearly retreating in horror when she saw his red glowing pupils.

« Leonardo ?! »

Using the motion to back off, she jumped out of reach and, landing gracefully on a desk, stared again at the ninja turtle with wide eyes, noticing the horns too.

Leonardo clenched his teeth, but didn’t try to hide.

In the meantime, Raphael had bulldozed a few adversaries on his own, helped by Donatello and Mickey, while Casey was mostly looking at the scene – and knocking things they had collected out of the hands of the unconscious ninjas littering the ground.

« Sorry, just an _assistance human_ doing his job, nothing to see there », he muttered while picking up the items – USB keys mostly. He would have to take their hacking devices too, since they probably downloaded some informations. He just hoped they hadn’t sent some through the internet.

« The building isn’t connected to the web, apart from the security framework. Perks of outsourcing », Donnie said to him while patting the chests and pockets of their fallen ennemis for phones. « They do everything via intranet, for safety reasons ».

« Yeah, it worked out so well for them », the hockey player growled. He remembered the guards outside.

Their remaining foes were fighting against the nunchaku-master and Raph, while Karai and Leo seemed to play a game of stares. No one moved, as they were simply looking at each other.

The kunoichi’s expression was torn between conflicted emotions, as she finally said :

« What happened to you ? »

Leonardo didn’t expect this reaction.

« What do you mean ? Don’t you have better things to think about right now ? »

Karai quickly glanced at her remaining followers.

« Like I can do anything… I see you got the upper hand as always… »

« You don’t look too much involved in this », Leo said in a cold tone. « Despite the fact you killed the guards outside ».

« They attacked us with riffles. No mercy for gunners » she said calmly. « As for the rest, I follow my Master’s orders, but you of all should know what I think about mutations and _enhancements_. It isn’t my path, and it’s unworthy of a true ninja ».

The leader flinched a bit.

« Is that an insult ? »

« I wasn’t talking about you… » Suddendly, a Foot ninja got violently propelled against the desk she was standing on, interrupting her and making her jump to the ground. Leo didn’t grasp the opportunity to attack her, and just waited.

Then, she saw Raphael’s shell, who had just sent the goon her way, from behind. She stared at it and looked back at Leo, her eyes going from one to another without a word.

« I see… »

Leonardo hasn’t expected her to remain so composed. In a sense, he didn’t know if he should feel happy for the fact she showed some concern, of be sad that she didn’t seem to care so much.

« Leo, are you going to fight her or what ?! » Raphael sounded pissed, and the leader could understand why. The sai-master couldn’t stand the kunoichi’s presence, all the more since Leo got so interested in her.

Karai immediately raised her weapon, pointing at the temperamental turtle.

« Don’t interfere, underling ! »

Leo bit his lower lip. Neither of those two were known for their diplomacy, and he didn’t want the situation to escalate.

« Enough, Karai ! You lost, get the hell out of here with what’s left of your goons ! ».

« Shut up Fearless ! That bitch insulted me ! » Raph was in full fighting mode now, and, wielding his weapons, plunged right at her. She was prepared for it and went for his throat, barely missing it while the ninja ducked to avoid the attack, and tried to get her flank.

Leonardo separated them by slashing right in the middle, both sharpened katanas cutting the linoleum on the floor.

« I said, enough ! »

« Get lost, Leo ! » the red-clad turtle wasn’t ready to let it go, and dealt a shoulder blow to the leader, who got most of the impact, and crashed against another nearby desk while the kunoichi was getting away.

_So weak… So dominated by your emotions !_

« Crap ! » the leader hissed between his teeth. His virtual invicibility allowed him to remain unscathed, despite the fact that Raph hadn’t held back at all while hitting him. He raised from the debris of the desk, the voice of the Oni ringing in his head and hurting him far more.

The emerald turtle had left to chase after Karai, who had gotten away in the corridor and down the stairs with four of her remaining ninjas.

_Your sibling is indeed an animal… You will never be able to tame him, unless you accept my power…_

« Never ! » the leader yelled. The pain was growing again, soon it would become unbearable. He knew what was happening, as time seemed to slow down around him.

The Oni was preparing an attack against his brother. _Again !_

« Leo ! » Mickey ran to his side and reached out his hand to help him get up. Panicking, the blue-banded turtle pushed him away violently.

« Go away ! The Oni… He is here ! Don’t come closer ! »

_He had to do something to keep the demon away from his brothers. _

Leo’s eyes were burning. The devil would soon emerge from his body, and there was no way he would be able to prevent another attack.

In the meantime, Casey and Donatello had joined Mickey, who’s eyes were tearing.

Looking one last time at his brothers and his human friend in complete dismay, Leonardo backed away and threw himself out the window, glass shattering everywhere, followed by the horrified voice of Mickey screaming his name.

Raphael was chasing Karai and her goons down the stairs, as they jumped from one floor to the other while throwing shurikens everywhere – which mostly bounced off against the ramps.

The emerald turtle was furious like never before, craving for Foot ninja’s blood.

Most of all, he was angry at himself for what he had just done to Leo. Of course, he knew his brother would just be fine, especially since he got completely revamped by the demon. However, the poor guy didn’t need to be tossed against furnitures like that. It was like Raph had completely forgotten their predicament, his glowing blood-like eyes, and had resumed to treat him like the lecturing freak his eldest once was.

Raphael was also aggravated by this whole cursed place, where they had to return because damn Shredder couldn’t simply be happy with playing evil ninja master, no, he always had to stick his nose in the most questionable things like a mob boss. And send his fucking adoptive daughter to do the dirty work, just to be sure Leo would then dance with his hormones instead of fighting properly.

_Man, he was in a mood to kill someone. _

They had reached the ground floor. He chased after them as they walked through the large entrance hall, no longer worrying about discretion. Suddendly, they all heard a violent crash outside, Raphael – and Karai – stopping right on their tracks.

_What was that ?_

Something heavy had fallen on a decorative glassware in the street, and a sense of dread filled Raphael’s mind, like he knew something was really, really wrong.

Karai and her acolytes had reached the doors and started to run around the building, heading towards the place where they had heard the smashing sound. It looked like the Foot Chunin was curious too, as Raphael followed them.

_He could feel his shell was cracked, and his bones broken into pieces. He hadn’t taken any precaution to slow down his fall, and now he was just lying there, in a sea of broken glass surrounding his body like cristal splattered with blood – his blood. The pain was excruciating._

_« So stupid of yours… But I’m not surprised… »The Oni said in a deep, calm voice. « You are going to die, for I can’t save you… You weakened me, remember… ? »_

_« So be it… We’ll be gone together » _Leonardo answered, his voice coming out with a bubbly sound – probably blood flowing his throat from an internal injury.

_« I can’t die, you fool…. I’m an immortal being… I will simply continue to exist in the astral plane and wait for another puppet… Unless…. »_

The dying turtle heard a sound close by. Someone was coming, but the steps were too faint to be one of his brothers.

_Karai… ?_

He could feel her presence growing closer. Why would she care what happened to him ?

_She had never shown any real interest in him… Not even once…_

_« That is where you are mistaken, mortal »_, he heard the demon say in his mind._ « You think you understand things… But until this very moment, you didn’t really know what it meant to have to die, especially like that, in the most painful way… Am I wrong ? »_

The Oni was playing with his mind in his last moments. A tear came to meet the blood flowing from his forehead.

_He would never see his brothers and father again._

A familiar head hovered above him. The Chunin was looking at him with a strange expression he couldn’t decipher. Her eyes were shining with the light of the Moon.

_She looked like she was about to cry. _

_« Since you are so weak… And since I still need you for my plan, even if I despise you and your kind… I will save you ! »_

Suddendly, the characteristical red flammes engulfed the turtle’s broken body and, surging out of it, they drowned the surprised kunoichi like a cascade of death, silencing her voice.

_NOOOOOO ! _Leo’s scream died in his blood-filled throat.

The energy blast turned around the limp body of the woman and violently went back to him, throwing him out of his glass grave up in the airs, and impaling his body from all sides.

Raphael was at a loss for words.

He had arrived when Karai was looking over something in the debris of the impact, her followers watching her, not knowing what to do, when suddendly a giant, whirling column of red flammes had plunged at her and engulfed her completely. Almost instantly, the blaze had left her body to go back to his brother – for it was coming from him – and lifted his body in the air, while he was screaming in pain.

It was purely horrific.

Little did the sai-master know that his brothers and friend were also watching the scene from the broken window, above them.

Karai wasn’t moving anymore, and her goons rushed to her inconscious body to take her and carry her away. They looked completely terrified as well, running for their life.

The emerald turtle let them go. Even if he had wanted to, he wouldn’t have been able to give chase anymore ; he couldn’t move a muscle, mesmerized by this improbable scene in front of him.

Those were the disgusting, reddish flammes of the Oni.

He had attacked Karai this time, probably hurting her badly.

_But why… How… ?_

The emerald turtle remembered that awful crashing sound.

_  
His brother had jumped from the floor they were in earlier. The eighth floor._

Suddendly, the column of crimson fire started to shrink and finally disappeared, leaving the limp body of Leonardo between the airs – levitating ten feets from the ground, like in an horror movie.

Raphael rushed to him and, ignoring the shards of glass that cut right through his naked feet, jumped to grab him. Instantly, the unconscious leader fell into his arms.

Despite being covered in blood, Leo was alive and breathing. The sai master couldn’t see any wound, not even a cut, on his skin.

Even his shell was pristine, all battle scars gone.

_Completely regenerated._

« I’m so going to kill you, Fearless… » Raphael said with a shaking voice, tears flowing through his eyes as he held his brother tightly and close to his heart.


	16. The Light at the end...?

**Summary for the Chapter:**

> Raphael once again carries an unconscious brother to their lair, while Donatello and the others try to address the situation and track what happened to the Foot clan Chunin. 
> 
> As for Leonardo, he is about to meet an unlikely ally…

It was getting pretty late in the night when they finally left, Donatello putting bandages on Raph’s feet. The bulky turtle didn’t even notice the deep cuts before their family doctor applied a disinfectant on them.

All the while, Casey was carrying Leo. Raph had insisted Mickey does not come to close to the leader. Who knows what the Oni was still up to ; better play it safe.

The youngest was so shaken, he couldn’t stop crying and reaching to take Leo’s hand, or touch him, as Casey tried his best to keep him away. The leader was still in a deep comatose, but breathing evenly. He looked peaceful again.

For someone who had just taken a dive to certain death, it was a sight to behold.

As soon as his wounds had been attended to, Raph got up and relieved Casey from his burden, carefully securing the leader – once again – on his deformed shell. He had thought of carrying him bridal style, but they had a long way to go to reach the lair. And he wanted to be home as soon as possible.

They kept silent all the way, Casey tagging along, feeling the heaviness of the situation.

_Leo had tried to kill himself._

_To get rid of the Oni and protect his family._

They had crossed another road, when Casey’s phone started to vibrate. He took the call and heard his girlfriend’s worried voice on the line :

« Casey ? Where are you ? » Casey often forgot April had psychic powers, and could feel when something was wrong. He couldn’t help but think that if she was able to get a hint of their troubles, Splinter would be in a far worse state when the turtles come home.

Especially with one of them completely out of service.

« Hello babe. How come you’re not sleeping ? Anyway, don’t worry, I’m with the guys. I was called to help deal with a Foot clan situation. »

« What ? Are you guys ok ? »

« Of course sweetie, how comes you always ask this question ? You’ve got the tougher boyfriend around ! » he tried to say playfully, but the heart wasn’t in it and his laugh sounded awfully forced.

« Are you sure you’re alright ? » April really sounded concerned now.

« Don’t worry. I’ll crash in your place tonight, ok ? Or this morning… I’ll tell you every details » he answered in a tentative light tone.

_Of course, he would leave out some details, at least for now. No need to add some crazy-worried big sister to this whole mess. _

Next to him, Mickey was still sniffing, eyes red from crying too much, swiping his face from time to time with his arm.

_Well, maybe some sisterly support wouldn’t be too much for this one, after all. _

After hanging up, the hothead gently slid his left arm behind the turtle’s shoulder, touching his naked shell – the yound DJ hadn’t put on his glass-like decoration, keeping his promise to remain in the shadows to Leo. 

« Easy there, Mickey-boy. Your big bro is alright, ok ? Just sleeping like a baby ».

« I know… But… » the youngest tried, mawning like a child and splutering, unable to calm down.

« I know, I know. But he’s alright, that’s what matters », Casey said in a mellowing voice, trying to soothe the seagreen turtle a bit.

In front of them, Donatello was walking in silence, HAL 5 fixing the inert body of their leader, zooming from time to time. What they didn’t know, was that all information about Leo's state were directly sent into the genius’ brain, who was silently assessing the situation.

He couldn’t wait to conduct some tests on Leonardo’s body, to confirm his theory and HAL 5 external readings. If he was right, every part of the jade green turtle’s body, internal or external, had been made anew. His organs were certainly like those of a newborn, save for the fact they would still have their adult size.

If the genius wasn’t mistaken, the leader was experimenting the result of a massive injection of self-organized stem cells, which replaced every cells, every DNA strands, and rejuvenated him as a whole.

_Thinking about the implications, Donatello felt thrilled. He had been right all along : not only did the Oni grant invincibility, he also gave real immortality – at a cost, of course. They were too high to see the details of the attack from their window, but from what Raph had told them, Karai had probably been severely hit._

_Knowing this, Donnie was sure her condition was too serious for the Foot clan’s medical facilities. She would be admitted somewhere, in a private clinic most logically. He would have to track her whereabouts down, to gather as much information as he could. _

His scientific mind was tingling pleasurably, while he watched his one brother who had cheated Death itself.

« Do you think he will wake up soon ? » the leading turtle – for now – had probably felt his brother’s gaze on his shell, and adressed him while looking straight ahead.

They were approaching the lair now.

« I don’t see why not », Donatello replied with a shrug. « He seems perfectly ok… »

« Yeah, for someone who just committed suicide », the red-clad turtle said between his teeth. « Without that fucking Oni, Leo would be dead. »

Donnie added nothing further.

When they arrived at the manhole closest to their home, Raph made his brother slide into his arms – still amazed by the now pristine condition of his plastron – and gestured Donnie to take care of him while he removed the cover.

« Please allow me », Donnie said, ignoring the unconscious turtle and kneeling down. HAL 5 robotic clamp then grabbed the heavy metal lid, and lifting it like it was nothing, tossed it on the side.

« Hmpf », Raph grunted, jumping down without glancing back, still holding Leo bridal style.

« You’re welcome », Donatello said, rolling his eyes before taking the ladder down.

« Ok, I think I’ll go », Casey said to Mickey before the young DJ could follow his brothers. « keep me updated with… Everything », he said awkwardly.

« Will do », Mickey answered. He had finally calmed down a bit, feeling reassured by his friend’s proximity.

« And call if you need something… Anything », Casey added. « April and I will be happy to help… »

« I know dude… Thank you for tonight… And… »

« Don’t mention it », the vigilante answered. « Ok, I'd better leave now ».

« Wait ! Will you… Tell her…? About what happened… » Mickey asked worringly, not willing to mention the _event_ itself.

« I guess I’ll have to… I’m not good at lying, especially not to a psychic girlfriend », Casey answered, embarassed.

« Right. I forgot… » Mickey said. « Then… Tell her to call us, ok ? We’ll fill her in on Leo’s condition ».

« No problem. »

With that, the human left.

Mickey sighted and followed his brothers down the hole, closing it after him. He wasn’t trusting his legs to jump like Raph had just done – while holding their brother, nothing less – and took the ladder instead.

He caught up with them and soon, they arrived at the lair.

Of course, their old father was waiting for them, knowing that something was not right.

« My son, I felt something terrible happen... » He then spotted Leo in Raph’s arms, and raised an eyebrown, since the turtle didn’t seem hurt.

Even his aura looked greater than before.

« He is alright, Sensei. Just asleep », Raph answered his father’s silent question.

« But he wasn’t alright just before, right ? » their master inquired.

_Why did they even try to hide anything from this all-seeing old rat ? _Donnie thought.

« He… » Raph couldn’t bring himself to tell their father. He looked at Mickey, who was close to tearing up again, then looked at Donnie.

So… It was left to him to explain everything.

_Again._

But this time, said turtle was fed up and didn’t feel like it at all. He frowned and pinched his forehead, closing his eyes.

« Can we just… Leo is alright, and that’s all that matters, right ? I believe he will soon wake up. In the meantime, why don’t you all just go to sleep ? I will stay with him and monitor his state, just in case », he said. He was starting to have a headache.

_No more explanatory session and obligatory mutual support, please._

Doubt pierced through Splinter’s eyes, but he didn’t argue further.

« Very well. I’ll be waiting for some clarification later », he said authoritatively.

« You’ll probably be able to ask Leonardo directly », Donnie retorted, finally taking the inert leader from Raph’s arms and carrying him towards the lab. « Good night for now », he added before closing the door in his family’s face.

They all looked at each other in disbelief.

« Fucking cold », Mickey finally hissed between his clenched teeth, his eyes red from all the tears he shed. 

**Meanwhile…**

Leonardo was floating in an empty space, his eyes closed. He felt strangely comfortable, like if he was in a mother’ womb. He could feel some strange blue light shining behind his closed eyelid – and it felt like a relief, not to see red for once.

It felt like he was lying on a cloud, his whole body and mind at peace.

_Where was he ?_

He was pretty sure it wasn’t the demon’s realm. It felt far too different – and warm, like an embrace from a loved one. Like he was back to being a turtle tot, falling asleep in Spliter’s arms while he was rocking him.

_So peaceful._

A soothing voice was calling out to him.

_Come to me, Leonardo…_

It couldn’t be the Oni. He had never called him in person, only giving him derogatory names like « mortal », « little one » and so on. So who was talking to him ? In a way, it felt familiar to what he had experienced so many times in the demon’s realm : a deep, strong voice speaking directly into his mind, behind his closed eyes. But this time, it didn’t hurt ; in fact, it felt like a caress on his soul, like if he was in a loving embrace. He didn’t want it to stop, but suddendly, he remembered what had happened to him.

The jump. The fall. The crash.

Did he die ? He certainly felt in heaven right now, but he was sure he wasn’t dead. He could still feel his body and hear the flow of his own bloodstream. His heart beating under his plastron.

He opened his eyes. He was floating in the nothingness, surrounded by strange lights who looked like lotus flowers. They were of an opalescent blue, like liquid cristal. In front of him, a path of aquamarine light opened, showing the way. He just knew he had to follow it. Moving his feet, he got gently put on the ground, like some invisible, gigantic hand was carrying him just before.

He started to walk. All around him, he saw glimpses of his own life : him as a turtle tot, cuddling with his father and preventing Donnie from annoying his other brothers. Him as a kid, training with the bo before he would receive his first katanas from their sensei ; him traveling to the North-East Gate and sumoning the Oni… By reflex, he reached to touch his horns, pretty sure they wouldn’t be there.

But here they were, as strong as ever. Did it mean his eyes were red too ? Like someone had read his mind, a beautiful shard of crystal slowly raised from the path, and he met his reflection.

His silvered eyes looked right back at him. He couldn’t believe it, but he felt it at his very core. The Oni was gone, here he was alone and protected.

Like a sanctuary.

Suddendly, the path became a shining circle, moving all around him, and he felt the ground shake from a strange, deep rumor. The light around him started to materialize into something else.

A giant, beautiful snake.

His skin was translucent and diaphanous, glowing from a perfect azure. The ninja turtle could only admire ths breathtaking dance of this huge, serpentine body around him. And then, he saw the face.

Two sharp, glazed lapis lazuli eyes were staring at him, seeing right through his being, contemplating his soul.

Everything was like the Oni : the power emanating from the creature, the energy… Yet it was not ; he felt at peace, and there was no malice in those pure blue eyes. The snake hissed and he felt the word echo in his mind, like he knew they would.

_Greetings, Leonardo._

The voice was soothing like a llulaby, and the katana-master had never felt more safe and at ease.

« Who… Are you ? » he managed to ask, his voice ringing like the voice of a small child.

_I’m the one who birthed you… I am your completeness, whole and separate at the same time._

He wasn’t surprised that the spirit – for he had to be one – would speak in tongue, like his father did sometimes.

« What do you mean ? » he still asked, willing to understand what was happening to him.

_You know who I am, even if you forgot_, the snake continued. _I created so many of you… To this very instant… Giving you the experience of the flesh and the blood, to help you learn… Experiment existence to its fullest… For I am the divine part of you, the energy that supports all life._

« Are you… A God ? » Leonardo suddendly felt weak at the knees. If he trully was in the presence of a god, on a holy ground, he should be kneeling. He was about to do so when the snake stopped him.

_Mortals may call me a god, but I am nothing but your soul, Leonardo._

« My soul ? » the jade green turtle was baffled. He had never thought that a soul could be so powerful, so immense compared to his carnal body. He felt at a loss : if he was conversing with his own soul right now, who was Leonardo ? What if the Oni was right, and he was only a flesh puppet ?

_Don’t get lost in your head, Leonardo. For you are a soul, a spirit and a body. I am you, and you are me. But until now, we never met during the span of your living experience…_

« You say you created many like me ? »

_No, I created many YOU… Transcending space and time, should it be here or at the other edge of the universe. There is no distance for the soul… There is no limit. _

« Then… Why… Why are you appearing before me now ? If there is so many Leonardos… »

_At this second, there is only you, and you are my pride. You are my last child…_

« Your last child ? I don’t understand ». Leo felt strange, being called a son by someone else than his father.

_You compeleted the cycle… You are able to travel through dimensions, like the one you call Father. You are wise, and live for the others. You freed yourself from the ego. And, for those reasons, I wanted to meet you for a long time, for we will be one again when you die. But this day had not arrived yet… Despite your will to end your life prematurely…_

Leo bit his lower lip. So this is what it was about.

« I had no other choice ! The Oni was about to attack my brothers ! If you are so mighty and powerful, if you can clone me by dozens, why didn’t you help by then ? I wouldn’t have had to try and die ! »

The spirit was unimpressed, and looked at him expressionless.

_I have no wish to interfere with the physical plane._

Of course. Leo should have known. Only demons do such things, since they don’t respect the established order of things.

But still…

« Couldn’t you have done something, anything to help, at least ? »

_I did._

Suprised, the ninja turtle looked at the snake.

_Those horns are a protection I granted you, when you called the demon to your side._

Flabbergasted, Leo touched them again.

_This blessing of mine allowed me to seal the core of your spirit inside, so that the Oni could not take control of your being. _

So… This is the reason why Leo could fight the demon in the astral plane. All this time, his soul had been there to help him. If only he had known sooner…

« What can I do to use your power to protect my brothers ? »

_Your sense of self-sacrifice, and your will to dedicate your life to others is the reason why you will be my last creation. As for now, you must find within yourself the strengh to use my power, which has always been yours and will always be._

This was cryptic, to say the least, but it would have to do.

_Difficult times are coming ahead, Leonardo…_ The deep, desembodied voice sounded almost… Sad, while saying this. The turtle was confused.

« Even worse than now ? How it that possible ? »

_Despite your will to fight and your courage, there is a loved one you will lose._

« What ! Impossible ! » the katana-master yelled. He hadn’t done all this, the battles with the demon, his… Attempted suicide, to lose someone dear anyway.

« There must be something I can do ! Tell me what to do, I’m begging you ! »

_There are souls you can’t save, my child._

Leo stopped, chocked.

What did it mean… ?

_You must go now, Leonardo. Time hasn’t stopped, and here, in the spirit realm, the hours go by more slowly than on the physical plane. You must go back to your family, for they are in danger now._

Urgh. Leo could feel his throat tighten up. He had to go back. However, he suddendly remembered what had happened when he was on the brink of death :

Karai looking over him, and then… The Oni…

« Karai ! The Oni attacked her too ! Do you know if she is ok ? »

_You will soon learn about her fate. Leave now, and protect the rest of your entourage. I will be with you every step of the way you have left._

Leo was really afraid now. Everything around him disappeared like a dream, and he suddendly got violently aspired through a dark tunnel, propulsed in his own body. Blincking, a huge pain in the abdomen, he looked around him and what he saw left him paralyzed.

**Notes for the Chapter:**

> We are closing in to the end fellas! At least for this part... For I foresee a sequel... Maybe ;-)


	17. Desperate time

**Summary for the Chapter:**

> While Leo is in the astral plane, terrible events are about to unfold in his home…

_Finally,_ Donnie thought.

_He was finally left alone with his brother’s body._

He had begun to slightly obsess over Leo’s condition, and the fact that he looked compeletely regenerated. The rejuvenation came from inside, that he knew for a fact. Quivering with excitement, he laid his brother down on the gurney. He was pretty sure everything internal would look pristine, and he wanted to document it for future use.

He removed HAL 5 and, letting him in a corner near his desk, went to get the echograph while whistling contently.

While he took ultrasounds of the unconscious turtle’s chest cavity, he couldn’t hide his joy. Leonardo looked like an adult newborn, and the genius’ eyes couldn’t help but linger on the perfect condition of his plastron and his skin, free of all the scars that traced a living story of the ninja's fights for survival.

Gently turning Leo over so as not to wake him up, Donatello took his Tphone out and took pictures of his shell and body at various angles, to compare them to previous shots. While manipulating his brother like an object, Donnie felt extatic.

_Coupled to what he had learned from the Oni, this was an incredible discovery. _

The remaining question was, whether this incredible condition was a one-time event – non-renewable – or a sustainable state for Leo.

_Only one way to know._

Donnie needed some material to proceed. He went away exploring the confines of the laboratory, and came back with an anaesthetic syringe and… A scalpel.

_He would start with a shallow cut on the muscular arms, and see if the leader was still able to bleed._

Mesmerized, he stared at the wound he had just inflicted to Leo, while it healed before his eyes. Like in those vampires fictions, save for the fact the leader didn’t need to fear the sun or consume blood to sustain himself.

He was invincible, now.

Donnie was ready to cut the jade green skin again, when the turtle woke up abruptly and grabbed the genius by the throat with one hand, squeezing it to the point of suffocating him as he looked straight into his eyes - Leo's eye sockets were completely red, like two rubies.

Too excited by his research, the genius hadn’t noticed the blue horns were gone again.

_It wasn’t his brother !_

« Argh… Let go ! »

_« how convenient that YOU, of all mortals, are here ! Remember me ? » _The turtle said, his face distorted in a hainous expression._ « I can’t wait for you to serve me ! »_

Donatello wasn’t suprrised to the least. However, while suffocating, he wondered for a second if their leader hadn’t in fact died, and thus let the demon take his place.

Suddendly, they heard a powerful roaring and the scientist saw his red-banded brother dive at Leo and throw him against the wall, behind the gurney, before trying to wrestling him on the ground.

« What the fuck Leo ! Are you crazy ?! »

All the commotion alerted Mickey and Splinter, who came running, at the exact moment when the possessed leader lifted Raph up and threw him at them, like he weighted nothing.

« It’s not him ! It’s the Oni ! He’s in full control! », the genius alerted them. They were all in danger now, him included, and he had no idea how to stop an incarnate demon set on destroying them. Performing a forward roll, he landed right near HAL 5 and skillfully equipped it in one go, activating immediately and pointing the gamma gun at the jade turtle who was coming at him in full speed.

Meanwhile, Raph was trying to get up while Splinter had managed to get out of the way. However, Mickey had taken the full impact of the sai-master’s shell, and was moaning in pain under the bulky turtle.

« Urgh dude, move! » he yelped.

The genius fired at their possessed brother, hitting him at the right shoulder and projecting him against the echograph, who disintegrated under the hardened body.

Two voices yelled in despair.

« Donnie ! What have you done ! » It was Raphael and Splinter, who looked at him with disbelief – and horror. However, they didn’t have time to recover from the shock, since Leo got up immediately, his eyes beaming from a red anger.

_« Always resorting to your coward’s tricks… Puny creatures, all of you ! »_ he hissed between clenched teeth before unsheathing his katanas.

_Why, oh why hadn’t he removed them before taking pictures,_ the genius thought in despair.

Twice, the demon had tried to kill him. He had thought that after their… _Talk_, the demon would leave him alone for a while, but no. The devil probably didn’t need him in good shape, _barely alive _would do the trick.

_You’ll be mine !_ The Oni shouted, piercing everyone’s brain with his sole voice before plunging again at the genius, who barely escaped the attack.

_Déjà vu feeling, anyone ?_

Raph managed to place himself again between his brother and the demon, and shouted :

« Run, Donnie ! He’s after you now ! Get away with the others ! »

_« The freak of nature »,_ the demon hissed at him. _« What do you think you will achieve, by sacrificing yourself ? »_

« I’ll protect my family ! » the red-clad turtle yelled at him, tears pulling in his eyes, while he reached for his sais. The situation seemed desperate, and he would have no other choice but to kill his own brother, or get killed by his hands.

It was a pure nightmare.

« I will never let you fight alone ! » Mickey screamed, running at Raph’s side.

« Go away ! » the red-clad turtle barked, trying to push him behind. « You have no chance against him ! »

« Neither do you if you fight alone », Splinter said, joining them in a combative stance. « I will never abandon my sons », he said while looking directly at this mockery of Leonardo – pure hate made flesh, with those dreadful, glowing eyes.

Raph knew he would not be able to make them leave, so he addressed the Oni directly :

« Where is my brother, you sonafabitch ! »

Even Donatello was hesitating, still cornered against his desk. HAL 5's camera was jumping from one opponent to the other, calculating the odds. They weren’t good, the demon was too powerful, even for the four of them.

_« Dead. I needed a body, and I got it ! »_ The Oni replied witha devilish smirk.

« You’re lying ! » Raphael was completely losing it and, in one swift move, him and his allies jumped at the demon.

No longer hesitating, Donnie joined them, HAL 5 ‘s arm targeting Leo’s flank and hitting him with all its might, sending him flying. They all heard the awful sound of shell cracking, but of course, the wound repared itself in a second.

« What the shell ! » Raph was competely taken aback, looking at Leo’s body. Almost immediately, the devil regained his strengh and landed a direct hit at Michelangelo’s abdomen – choking him and projecting his body against shelves. He crashed loudly, scattering books and broken test tubes glass everywhere.

_Everything would soon be destroyed in the lab_, Donnie managed to think, before aiming at the devil with his gun again.

_« Enough ! »_ in a second, the Oni was on him and, hitting him with a well-placed punch on the face, knocked him unconscious. Tearing off HAL 5 from the genius and lifting his body without breaking a sweat, the demon rushed into the opposite wall – shattering it into pieces – and ran away in the sewers with his hostage.

« Donnie ! » Raphael rushed after them, not before turning back and seeing his youngest brother on the ground, holding his tummy with a suffering grin.

« Go ! I’ll take care of him », Splinter screamed before reaching Mickey whose mouth was slowly filling with blood.

Biting his lip in despair, Raph forced himself to turn away and engage the pursuit in the sewers.

He started to run like crazy, being reminded of the prior event – the first attack, who left their little brother diminished. Conflicted emotions were running wild into his mind – it was his brother who got possessed, their leader, the center of their team. And he had kidnapped the brainiac, their only doctor. And well, Donnie was still his brother, evil or not.

He had to save them. No matter the cost.

He managed to catch up with them when the Oni arrived with his shipment in a larger crossroads, with a conduit going all the way to the surface.

_Asshole ! He wanted to get topside !_

If the demon managed to reach the outside world, Raphael would never be able to fight him. Especially since the sun would soon rise.

The Oni turned around and spotted him in the distance. Smirking at him with that awful smile of his, he started to jump his way to the surface, at incredible speed.

_He had to stop him !_

Suddendly, Raphael knew what he had to do.

As the plates slided down, he spreaded his wings and, taking his momentum, he rushed out and started to fly.

_Nothing mattered anymore._

_He had to save his brother._

Like he had always known how to fly, he rose into the air at the speed of a bullet and soon, reached their level and even passed them. Turning around, he closed his wings and fell with all his might on Leo, interrupting his run and making him drop Donatello. Both started to fall and Raph, flying again, managed to catch the genius and regain height.

His other brother crashed miserably on the ground, the red-clad turtle looking from above, still worried for his eldest. He heard a weak voice near his ear :

« I told you those wings could be useful… »

« Shut up, brainiac. Leo isn’t out yet ! »

Donatello’s face was awfully congested from the hit earlier, and Raph noticed that he was missing some front teeth. But the wounded turtled still managed to look down. The leader was already getting up, staring at them. Red flammes started to emanate from his body, revolving around him and concentrating.

« He is going to devour us », Donnie stated.

« What if I try to escape those flammes ? » Raph asked, maintaining his grip on him, his wings flapping gracefully.

« I don’t know if they have a range… Too many factors involved… » The genius started. Raphael couldn’t help but chuckle, looking at his nerdy brother with soft eyes.

They were probably about to die together.

« We won’t know if we don’t try », Raph said, preparing to take the higher ground. Suddendly, the heat they could already feel at their feet simply… Disappeared.

Leo wasn’t moving anymore, the red flammes regressing inside his body. His eyes were closed.

« Look ! » Donnie said, his voice shaking. « His horns… They’re back ! »

« What ? » Raphael looked closer. The genius was right. But they were gleaming like never before.

Blue light was emanating from the leader’s body, now. He inhaled and exhaled deeply, before opening his eyes.

They were still faintly glowing with red, but they could feel their leader was back.

« … Guys ? »

« Leo… ! » Raphael could have broken down in tears this instant, if he wasn’t still carrying a barely conscious brother. He wanted to start descending, but the eldest gestured him to stay away.

Leonardo was horrified. Whatever had happened, they weren’t in the lair anymore. And despite the distance, he could see Donnie had been badly beaten.

« Leo, we need to go ! Mickey is hurt too ! » Raph yelled, landing on a nearby ledge.

« Go. Take Donnie with you. I’ll take care of this, once and for all », Leo said.

« What ?!... No ! » Raphael wasn’t ready to abandon his brother. « I won’t let you do it alone ! »

« There’s nothing you can do to help, Raph. Let me do it, I’m begging you ! I need you all to be safe ! » Leo begged. « I will get rid of him, I promise ».

Now, Raphael was really crying.

Suddendly, the three of them heard a guttural roar petrifying their heart.

_« And you think you will win ? Without me, you would be a corpse ! » _The demon was laughing like a madman. Red flammes pulled again out of the leader’s body, this time, taking a solid appearance. For the first time, Raphael saw the demon’s appearance, exactly like the ones of the old japanese tales, a warrior in full armor, far bigger than the jade turtle, with a monstruous mouth and teeth ready to shred his opponent. Not to forget, twin gigantic blades in each hand.

« Raph, go! » Leo shouted, moving into position. His katanas were now shining like sapphires.

_Like in the astral plane_, Donnie tought while observing the scene from above.

As for Raphael, he knew he had to leave right now. Otherwise, the demon would probably try to eat them two to stand a fighting chance against Leo, who looked powered up like never before. Raph had no idea what this blue light meant, and he was scared to death for his brother, but he had to let him deal with the Oni. Alone.

However, the two adversaries were blocking the entrance of the sewers. The red-banded turtle had no other choice, but to take off and head towards the surface, praying there wouldn’t be too much people outside in those early hours.

The rising sun met his amber eyes as soon as he left their underground world, Donatello hiding his swollen face with one hand. He flew to the nearest building and help the genius sit on the rooftop.

He wanted to know what would happen next. Donnie thought the same, as they stared at the the precipice they had just left, holding their breath. In the midst of everything happening, Raph also hoped Mickey would be ok.

At ground level, Leo and the Oni were moving in circles, staring at each other with contempt. Never in his whole life, the leader had hated someone so dearly.

« _So, you have unlocked your soul’s potential ? And you believe, it will be enough to defeat me ? How laughable_ ». The demon was still taunting him, but Leo would have nothing of it.

Without a word, he threw himself at him and slashed, the demon barely managing to counter the attack.

« I will send you back to the astral plane where you belong », Leo simply said in a cold voice. Attacking relentlessly, he clearly had the advantage now.

_« You will never win ! You are nothing but a mere mortal, a weak creature ! »_

« I always bested you. All the time, I just didn’t know it. You could never dominate me, and resorted to cowardness to attack my brothers because you couldn’t have me. Now, be gone, monster ! » the ninja screamed, climbing the giant to his head, trapping it between his katanas and slicing it off in one swift motion.

In a howl of pain and a vortex of blazing flammes reaching the edges of the conduit, the Oni’s body exploded. Leo managed to protect himself behind his katanas, who’s blue light shielded him from the blast.

It was done. Finally.

Leonardo looked around, he couldn’t believe it was over. Laughing incontrollably, he felt on his knees, suddendly feeling exhausted.

Up above, the two brothers had seen the pilar of flammes and had rushed back to the entrance of the sewers to see what had happened. However, they couldn’t see anything.

« Erm… Raph ? A little help maybe ? » Donnie said.

« I’ve got you bro », he said, taking him in his arms.

They slowly descended through the conduit. When they eyes finally got used to the darkness of the sewer, they saw their brother kneeling on the ground, and ran to him as soon as they reached the floor.

He raised his head and looked at them, a shaking smile on his face. Gone was… Everything. No more red glowing eyes. No more horns.

He was free from the possession.

Raph got closer and looked intensively at his older brother, before hugging him, burying his face in the crevice of his neck.

« Leo, dude. I thought we lost you… Twice ! »

« I’m so sorry, Raph… » Leo muttered, his voice like a whisper, while retuning his brother’s embrace.

It felt so good to know he could be close to his loved ones again, without fearing for their life.

Donnie was leaning a hand against the wall, unable to stand on his own. That frigging demon had gotten him good earlier, and licking his lips, he noticed with disdain that he was missing two teeth.

_So… The Oni was gone._

« I’m glad you’re ok, Leo… But I believe Mickey was in a rather bad condition when we left », the genius said, spitting a little blood and bits of enamel with disgust.

The two turtles looked at each other and, nodding, they got up. Raph resumed his assistance duty with Donnie, and they ran back to the lair, Leo growing more and more horrified with the extent of the destruction the demon had left behind him.

Their father was sitting on the floor, Michelangelo in his arms, unmoving. He looked at Leonardo with surprise :

« My son, you are… »

« Free from the Oni, yes, Father », Leo answered, kneeling in front of their brother, Donatello coming closer, helped by Raph.

« I believe he’s in a coma… » Splinter said, his voice shaking.

« I can help him », Leo simply said, taking the young turtle on his lap with infinite care, and laying his hands on his body.

The leader closed his eyes, and the blue light Raph had seen earlier emanated again from him, spreading over Mickey’s body and entering it through the shakras points.

All the time, Splinter was staring at the scene with wide eyes, along with the remaining brothers.

Suddendly, the young DJ opened frightened eyes and looked around, slighlty panicked, particularly when he saw who was holding him close.

« Leo… ? »

« Don’t worry, it’s really me. You’re safe now, little bro. »

The family doctor was impressed.

Whatever the eldest had done, he had developed some kind of powers allowing him to heal without the help of the Oni.

« But how… ? » he started to ask.

« It’s hard to explain, Donnie. I just know that I can, deep down ».

« You may have unlocked your true potential, my son », Splinter said. « it happens when someone has reached enlightment during his lifetime ».

« Whatever this shit is, it’s working, and that’s all that matters » Raph said, kneeling beside Leo and patting Mickey’s head gently, who smiled at him in return. The bulky turtle had been shedding tears of joy continuously, and he couldn’t care less how it looked like.

He was happy. For the first time in what felt like forever.

« Dude, you’re a healer now ? Like in my games ?! That’s… Purely… Awesome ! » Mickey said, getting up all of the sudden and throwing himself at Leo who burst out laughing, embracing him too ; soon joined by Raph who squizzed them both tight, and their father at last.

It felt so good to be back.

In the background, Donatello had found a place without too much glass on it to sit down, watching his family in silence. The laboratory was completly destroyed, but at least, he appreciated the fact that he wouldn’t be left alone anymore to tend to everyone’s medical needs.

_A small consolation prize._

Suddently, four pair of eyes fell on the genius, and Mickey got up with a mischevious smile, heading straight for him, soon followed by the others.

_Oh no._

They all dived at him at the same time – Splinter included – and he could only reach for air desperately, also to protect his swollen face, as all shades of green and furry arms encircled him and snuggled close.

_Yep, everything was back to normal._

Donatello sighted silently.

_He had missed his chance._


	18. Shining in the dark

**Summary for the Chapter:**

> Peace has returned to the lair, and Raphael is set on learning how to use his wings to their best potential. However, Leonardo must live with the fact that the Oni put Karai on the verge of death to save the leader’s life, and that the kunoichi he had feelings for, and the biological daughter of his adoptive father, is now in a critical condition.
> 
> As for Donatello, there is something still weighting on his mind…

Leonardo had healed the genius’ face to the best of his new abilities, however, he couldn’t control them well for now, and of course, it didn’t involve growing teeth back. So Donatello had to fix some enamel implants for himself. Also, Mickey wasn’t completely cured either ; his liver remained in his shrinked state – after Donnie had managed to repair the echograph, with Raph’s help.

As for the emerald turtle, he had resumed his night patrols with Casey, haboring his wings proudly, determined to make the best of it – despite his friend nicknaming him « Tinker Bell » jokingly.

The leader had asked the genius to track the whereabouts of Karai, and learned that she had been admitted into a high-class, private clinic.

She was in a critical condition, needing a lot of various medical equipments to simply survive, and was also in a coma.

Leonardo had fallen into a depressive state afterwards, but decided soon that he would not dwell too long on the past. What was done was done. He would try to find a way to help her, learn to control his healing abilities and maybe, one day, be able to cure her before she crosses the rainbow bridge.

_Good luck with that_, Donnie had thought. He couldn’t get why the Leader was so obsessed with one of their enemis, as cute as she could be according to males’ standards. All things considered, Leo was still possessed, this time by human passions - despite his so-called « enlightment ».

_Onis got nothing on hormonal control. _

And him, Donatello, got left with a huge sense of loss too. He thought he had gained the upper hand, and had been prepared ; but no, nothing went according to his plan. All he was left with was some kind of magical, astral-mumbo jumbo assistant still learning how to be efficient. And some teeth missing.

_What a win._

He was looking at his screen without seeing it, scenes of the cameras in the sewers playing right before his eyes. One of the feeds was still on static mode. 

_He had forgotten to repair the destroyed cam._

Sighting, he went looking for spare parts in his lab - which had been cleared and emptied of all debris spilled on the ground, thanks to the whole family. Still, he now missed a lot of equipment, and would have to do many trips to have them back. And of course, to make things easier, he would never be authorized to step foot in the research center again, or go on a solo mission all by himself. It was a lost cause anyway.

Once equiped with what he needed, the genius went to the lair’s entrance, only to be stopped by a voice behind him.

« Where are you going, Donnie ? »

It was Leo. Those days, it was like the leader couldn’t let go of any of them, like he had missed the proximity he held so dear. Now that he knew he wasn’t a liability to them anymore, he had become very clingy – or at least, that’s what Donnie thought.

« Just going to repair the camera who got busted last time », the olive-green turtle answered absent-mindedly. « I’m not going far, so no need for a chaperon ».

« Still, I would be relieved if you let me go with you… » Leo insisted.

_The mother hen was back. Oh, how he hadn’t missed this particular trait of his older brother. _

« No need to, Leo, I swear. I won’t be long ».

« Dude, what are you talking about ? »

_Great. Now Mickey wanted to join the sewers party. _

« Listen, guys, I don’t need anyone for this, ok… ? I just want to be alone and do my thing, alright ? »

« You’re alone all the time when you barricade yourself in the lab. I’ll go with you. It’s not open to debate », Leo said in his leader tone.

« And I’ll come with you ! Did you know that my Oni-thingie music is a blast on Soundcloud ? I’ll take my recorder, you never know what could be mix-worthy today ! »

Leo looked at his little brother and shook his head, facepalming a bit. « I can’t belive you’re selling something with HIS voice on it… »

_PERFECTION_, Donnie thought, clenching his teeth. The bonehead and the mother hen, in arguing mode even.

_At least Raph was outside with Casey… By the way…_

« How come you never bug Raph for going topside, and you come after me for making a quick trip in the damn sewers ?! In the immediate vicinity of the lair ! » Now Donnie was pissed, which surprised both his brothers.

« You know he needs some training for his wings… And I can’t just tell him not to leave, he will go crazy, he can’t stand being stuck at home », Leo answered, this time hesitantly.

« Yeah, and what if I don’t want to stay home either ?! Have you thought about it ? » Donnie was yelling now, which was so unusual for him, the two turtles backed off on instinct.

« Dude, calm down… » Mickey said.

« Donnie, I’m just worried… » Leo tried in a soothing tone.

« Yeah, and when I want to enhance my oh-so-weak condition, since no one seems to trust my fighting abilities, you come after me again saying I’m cheating ! Make your damn mind ! In the meantime, I’m leaving, and I’m going alone ! Don’t you dare follow me ! », the genius barked, grabbing his bag and leaving without a glance back.

The two brothers remained stunned, at the entrance of the lair, looking at the scientist’s shell disappearing in the tunnels.

_Oh, he had enough of it. All of them. Their everyday reality. The fact that they believed he was some damzel in need, asking for constant supervision and protection. Him, Donatello, the mightest brain of the bunch, a genius confined in a recluse life in the sewers. Hiding like a freak, never able to live on the surface. _

_Condemned to remain hidden._

_It was so unfair!_

He arrived at the place. In the end, it wasn’t THAT close to the lair, and during his walk he had some time to calm down and think with a cooler head.

_There was nothing he could do to change his life. He only had one window of opportunity, and it shut on his face._

He spotted the busted camera. Completely out of commission, like he already knew. Then, he looked at the ceiling of the tunnel above him, and saw it.

Something glowing. Red.

The strange substance the Oni had produced. Even if only a little remained, it was still there, shining in the dark.

Fever clouded Donnie’s mind. He had to get a sample of it, now, before it would disappear completely. Cursing the fact he hadn’t taken a test tube with him, he thought about going back. But he didn’t want to confront his brothers again.

He had to act quickly. He just _knew_ this thick liquid was what he needed, right now.

_He had to do it._

In the living room, Leo was pacing around, going in circles, while Mickey had resumed playing his favorite game.

« Dude, seriously, stop, you’re going to burn a hole in that old carpet », the young DJ said to his brother.

« Mickey, don't you think I was too harsh with him ? Maybe he’s right, I should be more strict with Raphael… »

« Those two words don’t play out too well together bro, and you know the brainiac. You were right to cut the hothead some slack, you know. He really needs to get used to his wings. Even if he helped Donnie, he still feels a bit uncomfortable being… You know… _Different_ ».

« I know… »

Suddendly, a noise coming from the entrance alerted them. Donnie was there, looking at them with a wide smile.

Instantly, Mickey felt cold sweat on his shell.

_It was THE smile. The one the genius had when something was about to go terribly wrong, most of the time because of an experiment of his or something like that. _

It was a mystery, how their nerdy brother could get fascinated, instead of horrified, by the dreadful consequences of his own acts, or anything that would have left anyone else paralysed in fear. With everything happening lately, they had nearly forgotten how Donatello could be dangerous. But tonight was a strong reminder, as Mickey stared into his brother’s eyes, who was merely ignoring him.

« Donnie… ? Are you… Alright ? » Leo enquired, suprised by the look of satisfaction on Donnie’s face.

« Of course Leo », the genius answered, passing him and patting him on the shoulder. « Cam is functionnal. You see, I told you there was nothing to be worried about ».

« Right… If you say so… » Leo wasn’t so sure of himself while saying this.

_Something felt definitely off._

Donnie winked at him and went to the lab, closing the door behind him and putting an end to the conversation.

« Dude… Did he just... Wink… ? » Mickey asked, staring at the closed door.

_Finally. _

_Donatello was starting to hear HIS voice again, even if the ramblings were undiscernable for now. The Oni was weakened, after all._

_The genius had to act quickly, or he would never be able to control such powerful entity._

_This red goo had served as a physical medium to keep him between dimensions. Donnie was sure it had been made with Michelangelo’s liver, the Oni using it to anchor a part of himself in the physical real._

_A clever preventing measure, in case Leo would be able to overthrown him._

Trembling, Donatello gathered everything he would need. Luckily, he had locked those things away, and they hadn’t been destroyed by the Oni during the attack.

By the time he was finished, everything was quiet in the lair, and everyone asleep.

Well, except for Raph, who had yet to come back home. Donatello knew for sure that there was only three souls with him right now.

_After all, he could feel them, and even hear their heart beating.  
_

There was much left to do. He had only tackled the first part of his plan.

Without a sound, he left for the garage, taking the elevator.

_This time, no one would get between him and his goal._

Leo was fidgeting in his bed, sweating profusely. He knew it was a dream, since he hadn’t been back in the devil’s realm anymore. Still, it felt nightmarish, even if he couldn’t see anything around him. Just the nothingness, and suddendly a voice saying :

_I told you to be prepared to lose a loved one._

This soft, deep voice. It was the snake spirit, but he was nowhere to be seen. Panicking, Leonardo woke up, his heart beating like crazy.

Something was definitely wrong, he just knew it.

He then got up and, having no idea where to start, left his room and went to Mickey’s door. The youngest was sleeping peacefully and soundly. However, Raph’s door was still open, the red-clad turtle hadn't come back yet.

Looking downstairs, Leo saw that the lab was in the dark too. But Donatello’s room seemed to be empty ; where was he ?

At the same time, he heard a sound in the living room.

Raph was back and, yawning while hiding his mouth, he was heading for the kitchen, probably to grab some midnight snack.

« Raph, wait », the leader whispered.

« Arrgh ! Don’t sneak up on him like that Leo ! » Raph yelped, startled. 

« Sorry… Have you seen Donnie ? »

« Donnie ? Why ? » Raph asked, raising an eye ridge.

« He isn’t in his lab, nor in his room. »

« Strange ». The bulky turtle scratched his nose. « Maybe the garage ? »

« Let’s check ». They both took the elevator and, when they arrived, the lights were turned off there too. Donnie was nowhere to be seen.

Suddendly, they noticed that the battle shell had disappeared too.

« Crap ! » Leo exclaimed.

« What the shell ?! » Raph couldn’t believe his eyes. « Why did the brainiac leave like that ? It will soon be daytime ! »

« It may be my fault », Leonardo said, shame veiling his voice. He then proceeded to explain what had happened earlier.

« Screw it Fearless, there’s no way the brainiac would act on his guts like that ! All the more for such a stupid reason ! »

« Maybe he wanted to prove something ? »

« Prove what ? that he’s an idiot carelessly acting on a whim ? That’s my line Leo, and I doubt he suddendly found a fondness in mimicking me », Raph answered angrily.

They were finally happy, and that dumbass of a so-called genius had to ruin eveything by risking a morning stroll on the surface ! With their less discreet vehicle, no less !

« We can only wait for him to come back and not do anything stupid », Leo replied in a worried tone. « It’s too late to go topside now ».

« Let’s catch some shut eyes, and then we'll deal with his sorry ass », Raph answered tiredly. He already had received his share of strong emotions for the rest of his life, and only wanted some peace of the mind.

However, Donatello didn’t return the next day, nor the day afterwards. Despite them searching the entire city, they couldn’t find a clue of where he went. It was like he had disappeared into thin air, him and their battle shell.

« So weird », Michelangelo said while they were sitting at the table for dinner, with their father.

« What I don’t understand, is what triggered this behaviour of his », Splinter said, lost in deep thoughts.

« As if we knew what goes on in that sick brain of his… » the youngest retorted, before being smacked in the head by Raph.

« Don’t speak like that ! He’s still our brother », Leo lectured him.

« A brother does not leave in the middle of the night to go who knows where », Mickey muttered with a pout. « I’m sure he’s up to something evil », he added, looking stubbornly at the floor.

Leo couldn’t deny it. They all knew what Donatello was capable of. They had hoped that the recent events would have, somehow, calmed down this aspect of the genius psyche, but it turned out they were mistaken.

« Maybe we’ll learn something if we take a look at the lab ? » Raphael offered.

In Donnie’s lair, everything was pristine and ordered, like he had taken care to clean the place entirely before leaving – maybe to make any potential evidence disappear, as Mickey pointed out to them.

However, the youngest yelped when he saw the exosqueleton abandoned near the desk.

« Dude ! He left without the shell cheater! »

They all looked at the robot left behind, looking pitiful with his clamp lowered down on the floor, and his cyclopean camera off.

« Ok… This is serious », Raph said in a low tone.

Leo ran into the dojo, to check the weapon rake.

Only one simple, wooded bo was missing. The purple-banded turtle hadn’t equiped his enhanced weapon either.

« Guys… Those metallic parts… Those were the ones attached to his shell », Mickey said, pointing at metal pieces lying on the ground in a corner.

Donatello had removed them all.


	19. Betrayal

**Summary for the Chapter:**

> The Hamato clan is still looking for his missing member, but they are starting to find clues of what happened to him – or rather, what he seems to be doing right now.

Every single night.

They were patrolling every single night, looking for clues that could tell them where their missing brother had gone. Not to mention, that Mickey was now running low on his hormonal medication, and that he could be in danger.

Leo had decided to contact Leatherhead and tell him everything, to ask him if he could fix some replacement for their brother. The mutant alligator had immediately accepted to help, but he doubted he would be able to reproduce Donatello’s formula. They didn’t have the passwords to the genius’ computers, so he would have to start from scratch.

In the meantime, Leo and Raph were patrolling the night, letting the youngest at home to prevent any injury they couldn’t tend to. The leader had still yet to learn to control his ability, and the healing process left him exhausted. They could only resort to using his power as a last recourse. Which left the young DJ moody, even with the extra free time to play music and games.

One night, the team A ran accross a street and Leo stopped abruptly, motioning Raph to approach silently.

Ahead of them, they could count at least three bodies. Walking in the shadows away from the street lights, they came closer and recognized the Foot uniform on each of them.

They were all dead. Dread filled Leo’s heart when he couldn’t spot any external wound, not even the tiniest puncture mark. Raphael was watching him in silence, as the leader turned the corpses over and over, with growing consternation.

« What are you doing, Leo… ? » He asked in a soft voice, not willing to antagonize him. Last days had been rough for them, with a Mickey sulking at home, probably hiding his fears under his pouts. The sai-master was sure that the youngest was scared for Donnie, but also for himself since he would soon have to deal with his hormonal imbalance – unless LH managed to find a replacement.

They had no idea what this "imbalance" would mean for the seagreen turtle, and they didn’t want to find out.

« They have no wounds… No cuts, no traces of blows, nothing ! » Leo said in a low tone, eyes wide open.

_He knew what it meant._

_But he didn’t want to aknowledge it._

Suddendly, one of the body collapsed in his hands like an empty bag. Feverishly, the leader started to grope the belly of the dead ninja.

« Uh… Leo ?? » Raph was growing more and more concerned now, seeing his brother acting like he was crazy.

« There’s nothing inside… They are empty… » He muttered, letting go of the corpse.

_No more blood, no more internal organs._

« They have been emptied… From inside ».

Raph looked at him, realization hitting him like a punch.

The Oni was back. Probably more powerful than ever, judging by the number of his victims.

Suddendly, Raphael’s Tphone vibrated.

« What ! » he barked in it.

« Whoa, dude ! Calm down, it’s just me », Casey voice answered. « I got to tell you, seems like strange things are happening lately. I heard from a source that a bunch of Purple dragons had been killed last night. A dozen of them, just dropping dead like that in the middle of an alley », he told his friend.

« A… Dozen ? »

« Yeah, more or less. Weird uh ? and a bit spooky too. Unless they all had a bad case of braindeadness, I don’t know what happened to them ».

Raph nearly let the cell drop to the ground.

Fifteen victims at least. Seeing how powered up the Oni was just after attacking Karai, it couldn't mean anything good.

Leo was staring at him, not saying a word.

« I don’t understand, that thing cannot exist in the physical plane without possessing someone! And you got rid of him », he addressed Leo, still on the phone.

« Wait what ? » Casey answered.

« I believe he has found another medium », Leo said slowly, despair piercing in his voice.

_A willing one_, he added for himself.

His own Tphone activated, and picking it up, he saw his father’s number on it.

_His father never called._

Leo felt cold sweat running on his shell.

« Dad ? » the panic made the leader forget all formalities.

His father’s voice was barely more than a whisper, like the old rat was… Hiding somewhere.

« Leonardo, please come back with your brother as soon as you can. Donatello… Is back ».

And then, he hung up.

The two turtles rushed like crazy towards their home, jumping in the first manhole they could find. All the way down, they kept silent, concentrating on running as fast as they could and reaching the lair in a matter of minutes.

Leo stopped almost immediately, Raph crashing into his shell.

« What the fuck Fearless ! »

And then, the red-banded turtle saw him.

Donatello was sitting on the sofa in the living room, enthroned like a king. Their father and remaining brother were nowhere to be seen.

Leo noticed that the purple-banded turtle had left his bo next to him. A simple wooden stick, with no special features at all. Also, there was no hole in the genius’s shell, like he thought it would – since he had removed his so-called « enhancements ».

His shell was pristine.

His body too.

No more scars. No more marks. Nothing.

_Like an adult newborn._

« Evening, brothers », he welcomed them, a wide smile on his face. However, this smile of his was all teeth and not warm at all. He looked nothing like a friendly sibling.

More like an enraged dog, as he stared at them intensely, brown eyes meeting golden and silvered ones.

« Where have you been ? » Leo asked bluntly, casting side glances to try to locate his father and brother.

« On a pilgrimage, I would say », the genius answered, amused. He followed Leo’s eyes and added : « I believe Sensei and Michelangelo are hidding somewhere in the garage, probably waiting for your arrival to confront me ».

Suddendly, Leo remembered that Donatello never called Splinter « Father », let alone « Dad ». It was always « Sensei », or « Master ». Something respectful but impersonal, and cold.

« Well, I’m glad that pilgrimage of yours has ended. Now, I’m waiting for your explanations », Leo added boldly.

_What have you done, brother ?_

Acting on instinct, the leader placed himself between Raph and Donatello, shielding the emerald turtle to his dismay.

_They were all in danger. Leonardo just knew it._

Raph noticed some faint blue light emanating from his eldest’s hands.

« Taking it to the next level, I see »… Donatello said calmly, getting up slowly. « Funny. You never saw me like a real threat, did you, Leonardo ? Not until tonight, at least… » the genius continued, approaching the leader who backed off, making sure Raph stayed behind him.

« So Raph needs you to protect him, now ? Well well, who would have thought », Donatello said in a sing-song voice. « Not looking so tough now, Raphie… »

« Bro, what’s wrong with you now ?! You look even creepier than before ! » said turtle barked at him.

« Well, thank you… »

The genius got so close to the leader, Leo could now smell the scent left on his brother. Something he had never smelled before.

Sulfur. And death.

« Too bad, because you see, Leo… »

Donatello blinked. And opened red, glowing eyes.

« I need Raphael for a little experimentation… »

Jumping back, nearly knocking the sai-master down, Leo grabbed him by the left arm and literally threw him in the sewers, far from the entrance. Raph just had the time to wheel away and land on his feet before hitting the tunnel’s wall. He was looking at his brother’s shell from behind, trying to get a grasp of what had just happened, when red flammes suddendly engulfed him.

Like Karai before him.

« Leoooo ! » the emerald turtle yelled, a strong, hot wind blowing in his face.

« Stay away, Raph ! I’m ok ! » and indeed, the leader was fine, a halo of blue light protecting his body, repelling the flammes of the Oni.

« Why are you doing this, Donnie ?! Don’t you see you’re bein manipulated by him ? Whatever he promised you, it was a lie ! » Leo yelled in the face of his brother, who was at the center of the crimson whirlpool, not fazed at all and still smiling. 

« You still don’t understand, do you, Leo ? » a voice answered him, half-Donatello’s, half-demonic. The heat around the leader was slowly rising. Soon, he would have to move, or be burnt alive.

« I’m the one manipulating him… Controlling him… »

« You’re mistaken ! No one can subdue such a powerfull spirit, you can only defeat him ! »

« You’re the one in the wrong, dear brother », the distorded voice answered. Breaching the wall of crimson flammes, a olive-green hand appeared and went to cup Leo’s face – to his horror. Then, the head of his brother followed, those disgusting, red-glowing eyes staring at him. « I have total control over him, a feat you could never achieve. You could only fight him, again and again, until you got freed from his grip. That’s not what I want. I envisioned the greatness I could achieve, if I managed to use his nature again him. Make him believe I was weak, expendable… And then… Taking him by surprise, jailing him in my own mind… With a little help of modern technology, that is », the genius said in a soft voice, tapping his temple. « A new implant of my composition. Of course, you wouldn’t be able to see the scar now… Since the Oni completely regenerated me too, like he did for you. Such a blessing you let go, Leo ! I will never, ever understand you, but there is no need anymore, so be it… »

Leonardo wa horrified by what he had heard. « Are you crazy ?! Are you going to kill us all ? We are family, damn it ! » The leader hit the hand that was stroking him. « Stop this madness, or I’ll have no choice but to fight you ! »

« You don’t stand a chance, even with your divine blessing », Donnie answered, smiling even more. « You’re of no use to me, so I’ll get rid of you right now ». The hand caught Leo at the throat, choking him and lifting him in the air. Then, Donnie tossed him in the living room, clearing the way to the sewers where Raph was staring at him, reaching for his sais, eyes wide and gleaming in the darkness.

« The courage of a fool », Donnie said while coming closer to him. « You’re no match against me, I’m basically a god now »

« You’re nothing like a god ! You’re a monster ! » Tears were falling from the sai-master golden eyes, now.

« Stop ! » Leo hit the genius from behind, sending him against the opposite wall. With trembling arms, he unseathed his weapons, ready to strike.

« That should be easier than the previous fight », Donatello mused. « After all, none of you really liked me, am I right ? »

Leo kept silent, casting a glance at Raphael, pleading him to shut up.

« Stop this, Donatello. I’m begging you. We love you. You are our brother, and nothing will change this fact ».

« Yeah, you may be the biggest asshole in the whole universe, but we’re still a family », Raphael added, his lips shaking. « Don’t give in to that fucking demon ! »

« I see other challengers joined the party. Perfect », Donnie answered, looking behind the leader.

Leo turned his head to see his father and youngest brother run in their directions.

« Leo ! » they shouted.

« Stay away ! It’s not him, he is possessed ! »

« You’re tiring… If anything, I’m the one possessing him now. Anyway, it was nice to see you all one last time, but I have something to do », Donatello said. 

And then, everything turned red.

It was like a sea of glowing lava around Leo. Heat everywhere, burning him to the bones – but he wasn’t really burned, it was only a sensation which felt like torture.

Blinded by the bloody light, he heard screams in the distance.

Raphael was first.

Then came Mickey.

He heard something fall down next to him, and in the midst of the etheral fire, recognized the silhouette of his father, lying unconscious on the ground. He was still floating in a bubble of blue light, a sanctuary protecting him, when a face appeared just behind the crystal rampart.

_Don’t.Ever.Cross.My.Path.Again._

Gone was his brother’s voice, as red rubies stared at him. The Oni was talking directly to his soul.

And suddendly, everything turned dark.

**Later…**

At first, he only heard a deafening silence around him, and then he started to isolate some familiar sounds.

Drops of water falling in the pipes near him, creating a regular sound.

Someone breathing evenly at his side.

Raphael… Snoring ?

Leo got up immediately and looked around.

They were all lying down next to each others. He reached his father first, touching him. Everything seemed alright. He merely looked knocked out, starting to come to his senses, growling. He probably had some small concussion from the impact, earlier.

The leader then touched his youngest brother, who moaned but didn’t look like he was in any pain. Finally, he took Raphael in his arms, effectively waking him up. His brother looked at him with wide, blank eyes.

Something felt… Different. But what ? It was then that Leo noticed that the sai-master shell was resting on his right arm, and that he couldn’t feel the outlines of the dragonfly anymore.

Forcing Raphael to turn his back on him, to the turtle’s weak protest, the jade turtle saw that his brother's shell was like new. No more bug clinging to him.

« Raphael… Oh my god… »

« What ? What ! » The bulky turtle was fully awake now and getting really agitated, trying to free himself from Leo’s embrace.

« Dude, your shell ! »

Mickey had awaken too, and was staring at his brother’s back with amazement.

« Mickey ! Are you ok ?! » Leo asked, letting go of Raphael who fell face first on the ground.

« Leo, damn it ! » he cussed.

« Yeah, I’m alright… I feel like, hyper good right now », the youngest wondered, as he saw his father move next to him and help him getting up.

« What the hell happened ? » Mickey asked, looking at the little assembly with puzzled eyes. « Donnie was here, and then… Did he attack us or what ? »

« I… Don’t know », Leo said. He couldn’t find an explanation for all this. « Did he hurt you, Father ? »

« I… Don’t remember. All I know is that I tried to strike at him when I saw him grab Raphael… And then… Nothing »

« I saw you hit the ground », Leo said, touching his father’s head to try to heal him. But, as a matter of fact, he couldn’t feel any wound on the old rat’s skull.

« I don’t feel dizzy anymore… » Mickey said hesitantly.

They all looked at him.

They couldn’t be sure that the youngest was alright. They needed to look at his liver directly.

« Raphael, do you know how to use the echograph ? I believe Don… I mean, I think it got repared », Leo said.

He couldn’t bring himself to say his brother’s name out loud, now.

« I’ll give it a try. I took a good look at his liver when it got shrinked, so I may be able to make a comparison », the sai-master answered.

They all went back to the lair in a hurry, which wasn’t really far. Everything had happened near the entrance.

Mickey laid down, waiting for Raphael to power the device up. Then, mimicking what he had seen when Donnie used it, Raphael put it on his brother’s body. Fortunately, the process was automated.

« It’s here », the orange-banded turtle yelped. « The black thingie ! »

« It’s… Definitely bigger », Raph said, captivated by what he was seeing on the screen.

« Are you sure, my son ? » Splinter enquired.

« Let me take a look at the previous pictures », Raph said in a hurry, leaving and looking for it. Rummaging through various papers, he suddendly raised a page triumphantly.

« I knew he had printed it ! »

He put it right next to the screen, and they all saw what they hoped to see.

Mickey’s liver was back to his normal size. He wouldn’t need any medication anymore!

Everyone started to cheer, but Leo remained silent while he stared at the device.

_Why ?_

_Why ?!_

_Why did he save them, only to disappear ? Why did he kill those people ? Why did he give in to the demon ?_

_Was it his plan to save Mickey ? To help Raph ? _

_Or was it all part of an agenda, which suited him better ?_

« Father… Why did he help us ? » the leader finally asked.

« I can’t begin to understand what is going on in your brother’s head now », Splinter said in a sad voice, ruining the cheerful mood. « All I know is that he didn’t kill us. He didn’t even wound us ».

Leo broke into tears, leaning against a nearby desk, all the pression of the last months pouring out of him. He started to shake uncontrollably.

_You will lose a loved one._

The spirit had tried to warn him. But he wouldn’t listen. He was sure that he could protect them all.

But there was nothing he could do against the core nature of his own brother. Against the temptation of power, that clouded his genius mind with no hope for salvation.

Even knowing this, Leonardo couldn’t help but feel mortified.

He had failed Donatello.

**Notes for the Chapter:**

> This is the end guys! At least, for part 1... I already have a lot of ideas for a second part, if you are interested of course ;-)
> 
> I have a full-time job now so I don't think I'll be able to write anything anytime soon. But it is still a project of mine and I hope to be able to do it soon!


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